fix: potential crash when setting vibrancy

[codebytere]

Description of Change

Closes #29653.

Fixes a potential crash when a value is passed in for the vibrancy type which is not valid either owing to operating system version or the string itself. This will now simply no-op.

Checklist

• PR description included and stakeholders cc'd
• npm test passes
• PR release notes describe the change in a way relevant to app developers, and are capitalized, punctuated, and past tense.

Release Notes

Notes: Fixes a potential crash when setting vibrancy on macOS.

[dsanders11]

Build error due to unused variable after the change:

../../electron/shell/browser/native_window_mac.mm -o obj/electron/electron_lib/native_window_mac.o
../../electron/shell/browser/native_window_mac.mm:1393:26: error: unused variable 'vibrancyType' [-Werror,-Wunused-variable]
NSVisualEffectMaterial vibrancyType;

On line 1363 (vibrancy_type_ = type;) the input value is saved off, and looks like it's checked if that's non-empty in NativeWindowMac::UpdateVibrancyRadii. Does that logic need to change? With this PR line 1363 will still save off the input to NativeWindowMac::SetVibrancy even if it is a no-op due to it being an unrecognized/unsupported value.

[release-clerk]

Release Notes Persisted

Fixes a potential crash when setting vibrancy on macOS.

[trop]

I was unable to backport this PR to "12-x-y" cleanly;
you will need to perform this backport manually.

[trop]

I have automatically backported this PR to "13-x-y", please check out #29722

[trop]

I have automatically backported this PR to "14-x-y", please check out #29723

[trop]

@codebytere has manually backported this PR to "12-x-y", please check out #30491