Enable searching for Flutter plugins specifying supported native platforms (e.g. Android, iOS)

[mit-mit]

When searching among Flutter packages, support narrowing the search to only packages that work on a particular platform (android, ios, web, desktop)

[mit-mit]

Related bug for package detail page: #144

[mit-mit]

Blocked on flutter/flutter#10288

[kevmoo]

@mit-mit Moving this to M4. We can re-triage once there is a plan on the flutter side to provide the needed info

[isoos]

@mit-mit: what is the latest on detecting whether a package works on ios, android or both?

[kevmoo]

I marked this as M4 – since we have no plan in the short term to address this

[mit-mit]

Correct, we don't have platform support for this yet.