Remove unused local bindings

[ansien]

Removes three Luau lint diagnostics by deleting the unused success = true declaration immediately shadowed by the following pcall result, and dropping the unused error_message binding from the page-advance pcall.

Both pcall calls, their consumed success values, error handling, and queue cleanup remain unchanged.

Validation:

• git diff --check passes.
• Luau LSP 1.69.0 with Roblox definitions reports two LocalUnused warnings and one LocalShadow warning before this patch, and none of those warnings afterward.
• The same consumer analysis setup reports 98 type errors both before and after this patch; this change does not claim to resolve those or make full analysis pass.
• No Studio or DataStore execution was performed for this lint-only change.