Run mobile tests on PR

[aguestuser]

Value Statement

As a where@ maintainer
I want to see results of unit and UI tests for all pull requests
So that I know that Android patches don't break iOS code (or vice versa)
And I can merge PRs efficiently and confidently
And focus my inspection of PRs on code review and feedback

Acceptance Criteria

Given	When	Then	And
A contributor submits a PR	All tests pass	I see a green checkmark next to the PR
A contributor submits a PR	Tests fail on either Android or iOS	I see a red warning next to the PR	I can click on a link to inspect test failures
A contributor submits a PR	The PR has more than than 80% test coverage	I see a green check next to the PR
A contributor submits a PR	The PR has less than 80% test coverage	I see a red warning next to the PR	I can click on a link to inspect coverage gaps
The PR has failed tests	I try to merge the PR	I won't be able to
The PR has insufficient code coverage	I try to merge the PR	I won't be able to