build(deps): bump packaging to 26.3 to resolve wheel>=24.0 conflict

[Tatamis]

Fixes #3418.

requirements.txt pins packaging==23.2, which conflicts with wheel>=24.0 (installed transitively) and forces pip to downgrade whatever packaging version was already present:

Using cached packaging-23.2-py3-none-any.whl (53 kB)
Installing collected packages: packaging
  Attempting uninstall: packaging
    Found existing installation: packaging 26.3
    Uninstalling packaging-26.3:
      Successfully uninstalled packaging-26.3
ERROR: pip's dependency resolver does not currently take into account all the packages that are installed. This behaviour is the source of the following dependency conflicts.
wheel 0.48.0 requires packaging>=24.0, but you have packaging 23.2 which is incompatible.

Bumped the pin to the current latest release (26.3), matching the version already implicitly present in the reporter's environment.

packaging.version.parse, the only API caldera uses directly (app/utility/base_world.py), is unaffected by the bump — verified locally.

Test plan

• pip install -r requirements.txt resolves cleanly with no conflicts (tried both uv pip and plain pip).