Launch tag type parameter for AdSense & GAM

[keithwrightbos]

Original code change introduced in #30764 wrapped in experiment flag. Launching change.

[amp-owners-bot]

Hey @Jiaming-X! These files were changed:

extensions/amp-ad-network-adsense-impl/0.1/amp-ad-network-adsense-impl.js

Hey @jeffkaufman! These files were changed:

extensions/amp-ad-network-adsense-impl/0.1/amp-ad-network-adsense-impl.js
extensions/amp-ad-network-doubleclick-impl/0.1/amp-ad-network-doubleclick-impl.js
extensions/amp-ad-network-doubleclick-impl/0.1/test/test-amp-ad-network-doubleclick-impl.js

[jeffkaufman]

Confirmed experiment was neutral, as expected, and code cleanup looks correct

[lannka]

for easier rollback, i suggest we first launch it with config only change. then follow up a clean up PR later when things are stable.

[lannka]

communicated offline, pure config change can not launch this feature 100%.