Updated flutter/examples to further conform to new embedding: removed references to FlutterApplication, deleted all MainActivity's that were not necessary, removed all direct invocations of GeneratedPluginRegistrant. (#22529) (#44782)

This reverts commit 99cd4403.

This reverts commit 46edc802.

* Fix device lab tests

* Migrate examples to the Android embedding v2 (#43221)

This reverts commit b49ffa81.

This reverts commit 30f33d6c.

Fixes https://github.com/flutter/flutter/issues/26544

* Rev Android Platform to 28 for bots

* push all to 28

* include platform tools update

This version honors flutter tool's --build-number/--build-name flags.

This reverts commit 8acc058c.

Reverts #25483

Reason for revert: it seems to break the flutter_gallery_instrumentation_test post-submit test.

TBR: @sbaranov

This version honors flutter tool's --build-number/--build-name flags.

This reverts commit 751c083f.

Our buildbots need to be upgraded to a newer version of the Android SDK.

This reverts commit 59bb2dba.

This reverts commit 0f557e72.

This reverts commit dac1baf4.

* android templates should add density and screenLayout to config changes

* update the rest of the manifests

This reverts commit 36e3b103 to make the build green.

This reverts commit 25b1d43a.

This reverts commit 05d6b08f.