[Housekeeping] Update CI Pipeline to use macOS Sonoma and Xcode 15.3.0

[TheCodeTraveler]

Description of Change

This PR updates our CI pipeline to use the latest version of macOS, Sonoma, and the latest supported version of Xcode, v15.3.0.

[TheCodeTraveler]

According to the docs macOS-latest still points to macOS 12 for some reason 🤷‍♂️

https://learn.microsoft.com/en-us/azure/devops/pipelines/agents/hosted?view=azure-devops&tabs=yaml#software

[TheCodeTraveler]

For some reason the sample app build fails when using Xcode 15.3 due to a configuration problem on the sever; it looks like they didn't install the macOS SDK (likely, they only installed the iOS SDKs):

2024-06-21 18:07:24.567 xcodebuild[5902:28583] Writing error result bundle to /var/folders/ft/pj103c817z9fx96nqdg321yh0000gn/T/ResultBundle_2024-21-06_18-07-0024.xcresult
  xcodebuild: error: SDK "/Applications/Xcode_15.3.0.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk" cannot be located.

I reverted the Build Sample App pipeline to use Xcode 15.2.0, keeping the Build Library pipeline at Xcode 15.3.0.