These landed upstream

### What has changed
- Adds a param to `tvos_extension` that lets the user select entry point
for the extension (either `TVExtensionMain` or `NSExtensionMain`).
- Adds tests for the change.

### Why it was changed
- Modern tvOS extensions are loaded via Foundation's `NSExtensionMain`
- I reported the issue here:
#2812

…ace" in dossier codesigning. (#2835)

PiperOrigin-RevId: 566315443
(cherry picked from commit c4cbd82)

Co-authored-by: Nicholas Levin <[email protected]>

…y, and it is a no-op now. (#2836)

PiperOrigin-RevId: 585665894
(cherry picked from commit 4d95005)

Co-authored-by: Nicholas Levin <[email protected]>

…ations with watchOS apps (#2838)

#2804 introduced in issue
where comparisons with `platform_type` are always negative.
`platform_type` is of type `apple_platform_type` and cannot be compared
with `string` directly.

…2842)