chore: remove abort-controller polyfill

[gameroman]

Description

Removes abort-controller polyfill

Scenarios Tested

Sample Commands

[gemini-code-assist]

Code Review

This pull request removes the abort-controller polyfill from the project's dependencies and various source files. The review identifies that this change will cause runtime TypeError exceptions in src/apiv2.ts, src/emulator/auth/operations.ts, and src/emulator/taskQueue.ts because the native AbortSignal.reason property is read-only and cannot be manually assigned. The feedback recommends using the controller.abort(reason) method for cancellations and refactoring 'as any' type assertions to adhere to the repository's TypeScript style guide.

[joehan]

/gemini review

[gemini-code-assist]

Code Review

This pull request removes the abort-controller dependency in favor of native AbortController support. It refactors src/apiv2.ts, src/emulator/auth/operations.ts, and src/emulator/taskQueue.ts to remove manual monkey-patching of the AbortSignal and updates abort() calls to include a FirebaseError. I have no feedback to provide.