fix: save dialog extensions should be deterministic

[codebytere]

Description of Change

Closes #25152.

The extensions were being added to an NSMutableSet previously, which caused nondeterministic ordering for the first one to appear in the UI when the dialog appeared. This fixes that by leveraging NSOrderedMutableSet to maintain ordering.

cc @jkleinsc @zcbenz @MarshallOfSound

Checklist

• PR description included and stakeholders cc'd
• npm test passes
• PR title follows semantic commit guidelines
• PR release notes describe the change in a way relevant to app developers, and are capitalized, punctuated, and past tense.
• This is NOT A BREAKING CHANGE. Breaking changes may not be merged to master until 11-x-y is branched.

Release Notes

Notes: Fixed an issue where filters set in dialogs on macOS would have nondeterministic ordering.

[release-clerk]

Release Notes Persisted

Fixed an issue where filters set in dialogs on macOS would have nondeterministic ordering.

[trop]

I have automatically backported this PR to "10-x-y", please check out #25192

[trop]

I have automatically backported this PR to "11-x-y", please check out #25193

[trop]

I have automatically backported this PR to "9-x-y", please check out #25194