fix(macos): prevent indefinite hanging if screen capture is not granted

[cathyjf]

Description

Currently, if Sunshine has not yet been granted the screen capture
permission, the program simply hangs indefinitely on startup when it
attempts to probe for usable encoders. This is not desirable because
it prevents testing and using all of the parts of Sunshine that do not
require the screen capture permission.

With this patch, the encoder probing will simply fail instead of
hanging indefinitely if Sunshine does not yet have the screen capture
permission.

Note that Sunshine already prints out an error message telling the user
that the screen capture permission is needed. The bug is that Sunshine
currently indefinitely hangs shortly after printing that message.

Screenshot

N/A

Issues Fixed or Closed

N/A

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Dependency update (updates to dependencies)
• Documentation update (changes to documentation)
• Repository update (changes to repository files, e.g. .github/...)

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated the in code docstring/documentation-blocks for new or existing methods/components

[ReenigneArcher]

Thank you for the PR. The suggestions are mostly to address linting failures.

[codecov]

Codecov Report

Attention: Patch coverage is 66.66667% with 2 lines in your changes missing coverage. Please review.

Project coverage is 11.06%. Comparing base (c54664b) to head (2b4610e).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
src/platform/macos/display.mm	33.33%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3360      +/-   ##
==========================================
+ Coverage   11.05%   11.06%   +0.01%     
==========================================
  Files          99       99              
  Lines       17231    17237       +6     
  Branches     8034     8035       +1     
==========================================
+ Hits         1905     1908       +3     
- Misses      12641    12784     +143     
+ Partials     2685     2545     -140     

Flag	Coverage Δ
Linux	8.35% <ø> (ø)
Windows	5.23% <ø> (ø)
macOS-13	13.62% <66.66%> (+0.02%)	⬆️
macOS-14	12.62% <60.00%> (+0.04%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
src/platform/macos/misc.mm	8.77% <100.00%> (+1.02%)	⬆️
src/platform/macos/display.mm	40.35% <33.33%> (-0.73%)	⬇️

... and 22 files with indirect coverage changes

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud