fix "your browser not supported" messages on android webviews

fixes: CNVS-14316

test plan:
* in the android native app, open anything that
 loads in a webview
* you should not see a message of "Your browser
  does not meet the minimum requirements for Canvas..."

Change-Id: Ic2dda05b54155e03923afaabcbe9ebd1066949f3
Reviewed-on: https://gerrit.instructure.com/37826
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Jeremy Stanley <jeremy@instructure.com>
Product-Review: Jeremy Stanley <jeremy@instructure.com>
QA-Review: Clare Strong <clare@instructure.com>