[GH] Fix gradle flags argument
[GH] Fix gradle flags argument

We were not passing gradle flags properly due to a type.

Bug: n/a
Test: CI

This is an imported pull request from https://github.com/androidx/androidx/pull/425.

Resolves #425
Github-Pr-Head-Sha: f249eb2d8f244a1ea9a19f16415ac874390d0ad2
GitOrigin-RevId: dd3e6b1946a8dab023aeb311c5377fb0f30ae44e
Change-Id: I7e16c574ebe53b795eec1122da28fb8216fee7a2

androidx/androidx,AndroidX/androidx,AndroidX/androidx,androidx/androidx,androidx/androidx,AndroidX/androidx,androidx/androidx,AndroidX/androidx,androidx/androidx,AndroidX/androidx,AndroidX/androidx,AndroidX/androidx,AndroidX/androidx,androidx/androidx,AndroidX/androidx,androidx/androidx,androidx/androidx,AndroidX/androidx,androidx/androidx,androidx/androidx