Remove obsolete classes ActionProxyReceiver and DeleteScreenshotReceiver

Unused since intents are now created and passed through
ActionIntentCreator/ActionIntentExecutor.

Screenshot deletion code has been obsolete for some time.

Bug: 287452614
Flag: NONE
Test: manual, atest
Change-Id: Ie802e1feb80c46f4128f778fb46cd8fd66d12b0f