Fix App ID reuse when bundle identifier casing changes

[Else00]

Apple treats bundle IDs as case-insensitive, but isideload used exact string comparisons when looking up existing App IDs.

When an IPA changes an extension identifier from OpenYoutube.Extension to OpenYouTube.Extension, isideload attempts to register the same ID again, causing developer error 9401.

This patch:

• Matches existing App IDs case-insensitively.
• Preserves Apple's registered spelling in the main bundle and extensions.
• Keeps exact-keyed provisioning profile and entitlement lookups aligned before signing.
• Fails before mutating bundle identifiers if a required registration is missing.

Validation:

• cargo check passed for the isideload library on arm64 macOS using iLoader's locked dependencies.
• rustfmt --check passed for the modified application module.
• iLoader was successfully rebuilt for arm64 macOS before this test-only removal.
• Live installation of the affected YouTube IPA has not yet been verified.

Reference: https://developer.apple.com/help/glossary/bundle-id/

[nab138]

Looks good to me on a quick glance, I will properly review and test either today or tommorow.

Also, while isideload definitely needs tests, right now it has none, and it doesn't make sense to start introducing them with this PR. I will revisit adding tests to isideload as a whole later on, but for now, could you remove the tests?

[Else00]

Yeah sure!