[camera_web] Fix TypeError when reading the torch capability

[0xharkirat]

What broke

setFlashMode and takePicture threw on any camera that has a flash.

The Image Capture specification declares sequence<boolean> torch in
MediaTrackCapabilities. package:web is generated from that specification, so
torchNullable was typed JSArray<JSBoolean>?.

No browser ships that shape. Chromium and WebKit both declare a bare boolean torch.
Reading the property threw before the torch could be applied. The error depends on
the compiler:

Compiler	Error
DDC	TypeError: true: type 'bool' is not a subtype of type 'JSArray<Object?>?'
dart2js	NoSuchMethodError: method not found: 'gq'
dart2wasm	ArgumentError: Invalid argument(s)

The same line held two more defects:

• .first gave the wrong answer for [false, true]. A specification-shaped sequence
  lists the values the source accepts, so that means the torch can be turned on.
• .first threw StateError on an empty sequence.

The fix

Read torch as JSAny? and add canEnableTorch, which accepts either shape and
returns false for anything else.

A sequence is answered with any instead of first, and is only trusted when every
element is a boolean. Anything unrecognised raises torchModeNotSupported instead of
crashing, and prints a debug-only warning so the shape can be reported.

Test matrix

Browser reports	Before	After
true	TypeError	torch on
false	TypeError	torchModeNotSupported
[false, true]	wrong answer	torch on
[true]	torch on	torch on
[false]	torchModeNotSupported	torchModeNotSupported
[]	StateError	torchModeNotSupported
key absent	torchModeNotSupported	torchModeNotSupported
'yes'	TypeError	torchModeNotSupported + warning
['yes']	TypeError	torchModeNotSupported + warning

Nine cases are covered by integration tests. Six of them fail without this change.

Devices tested

All nine shapes were run through the real plugin code on each of these. All passed.

Device	Browser	Result
Moto G56 5G, Android 16	Chrome 151	9 / 9
macOS 26.3	Safari 26.3	9 / 9
iPhone 17 Pro simulator, iOS 26.1	Safari	9 / 9
macOS 26.3	Chrome 151, dart2js and dart2wasm	9 / 9

On the Moto G56 the rear camera reports torch: true as a bare boolean, and the flash
now turns on. The front camera does not report the key at all and raises
torchModeNotSupported as expected.

What was added

• canEnableTorch on NonStandardFieldsOnMediaTrackCapabilities, which reads either shape.
• A debug-only debugPrint warning for a shape that is neither, so an unknown browser can
  be reported rather than failing quietly.
• Nine integration tests covering every shape, plus a check that a recognised shape never warns.
• A CHANGELOG entry and a version bump to 0.3.5+6.

What was removed

• The JSArray<JSBoolean>? type on torchNullable, which no browser matches.
• The ?.toDart.first.toDart ?? false chain in _setTorchMode.

Issues fixed by this PR

Fixes flutter/flutter#191384

Pre-Review Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the AI contribution guidelines and understand my responsibilities, or I am not using AI tools.
• I read the Tree Hygiene page, which explains my responsibilities.
• I read and followed the relevant style guides and ran the auto-formatter.
• I signed the CLA.
• The title of the PR starts with the name of the package surrounded by square brackets, e.g. [shared_preferences]
• I linked to at least one issue that this PR fixes in the description above.
• I followed the version and CHANGELOG instructions, using semantic versioning and the repository CHANGELOG style, or I have commented below to indicate which documented exception this PR falls under.
• I updated/added any relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or I have commented below to indicate which test exemption this PR falls under.
• All existing and new tests are passing.

🤖 Generated with Claude Code

[gemini-code-assist]

Code Review

This pull request updates the camera_web package to handle different browser implementations of the torch capability. In pkg_web_tweaks.dart, torchNullable is changed from JSArray<JSBoolean>? to JSAny? to accommodate both bare booleans and boolean sequences. A new canEnableTorch getter is added to parse these types, and integration tests are introduced to verify the capability parsing across various formats. No review comments were provided, so there is no feedback to address.