fix(core): guard strings.Split index in AppArmor annotation parsing

[bhuvan-somisetty]

Purpose of PR?:

UpdateContainer's AppArmor annotation loop indexed into strings.Split(k, "/")[1] and strings.Split(v, "/")[1] without checking the length of the returned slice. Any pod annotation key without a /-separated container name, or a non-unconfined value without a /-separated profile, made strings.Split return a 1-element slice and panicked the goroutine handling pod updates.

This pulls the parsing logic into parseAppArmorAnnotations, guards both splits with a length check, and skips + logs a warning for a malformed annotation instead of indexing out of range.

Fixes #2813

Does this PR introduce a breaking change?

No.

If the changes in this PR are manually verified, list down the scenarios covered::

• Added TestParseAppArmorAnnotations covering: well-formed unconfined annotation, well-formed localhost/<profile> annotation, a bare annotation key with no container suffix, a value without a / separator, unrelated annotations, and nil annotations.
• go build ./... and go test ./... pass locally.

Additional information for reviewer? :

Checklist:

• Bug fix. Fixes core: unguarded strings.Split index in AppArmor annotation parsing can panic the daemon #2813
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• PR Title follows the convention of <type>(<scope>): <subject>
• Commit has unit tests
• Commit has integration tests

[bhuvan-somisetty]

Hi @achrefbensaad @Aryan-sharma11 @AryanBakliwal, would appreciate a review on this whenever you get a chance. It fixes a daemon panic in the AppArmor annotation parsing path (issue #2813). Thanks!