Improving build error messages when build fails due to missing wheels

[pjfan]

Description of changes

I added more helpful error messages (via the install_hint parameter on _pip_install) when build iOS and build macOS fail. I also added a new install_hint parameter to _install_app_requirements per suggestion so that it could be passed in directly instead of having to get passed in via pip_kwargs.

What problem is solved

build macOS and build iOS commands can sometimes fail because of a single missing wheel for a particular platform's version of a library.

Ex. 1 - a project that relies on a version of numpy before 1.2.0 won't be able to build on macOS if universal_build=true because there's no arm64 wheel for numpy versions before 1.2.0.

Ex. 2 - accidentally deleting the iphonesimulator wheel will cause build iOS to fail even if iphoneos is present but the error message won't indicate this / will make it sound like both wheels are missing.

What issue is this PR related to

Fixes #2230

PR Checklist:

• All new features have been tested
• All new features have been documented
• I have read the CONTRIBUTING.md file
• I will abide by the code of conduct

[freakboy3742]

This looks great; the one missing piece at this point is some extra test code to verify that the helper messages are being included when required.

[pjfan]

Apologies for the delay, but I made the changes and added two tests. Not super familiar with pytest so let me know if the tests make sense and/or if they need modification.

Also rebased the branch with main.

[freakboy3742]

Thanks for that update; two problems noted inline:

1. The error message for the macOS case is incorrect, as the universal_build=False fix won't work if the initial install fails. If that build fails, the problem is that either wheels for the native platform aren't available, or the minimum macOS version for the app doesn't match the available wheels.
2. You've added test cases, but you haven't covered all the possible failure modes.

[pjfan]

Updated tests to test for each error mode

[freakboy3742]

Awesome - thanks for those updates!

I've made some cosmetic tweaks to the error message text, but otherwise, this is good to land - Thanks for the PR!