[ALPHA PHASE] Prompt Frequency Capping Flow

[justinchou-google]

b/299846493
https://docs.google.com/document/d/1H99mlR47aZZv_ZsCRkI6Iv_WUcpwaoeGgCExWSkdYCI/edit?resourcekey=0-9djhO0eRtzh5bMMrZ1dtBg#heading=h.634013igpqpv

Extends triggering flow to follow new prompt frequency capping. Expands AutoPromptConfig model to handle FrequencyCapConfig. Refactors some action eligibility checks. Also refactors computation of prompt delay. Updates openaccess subscription flow to follow audience action order. Display delay is extended to all dismissible prompts. All changes guarded by experiment flag.

TODOs:

• (b/300963305): manually triggered prompts should also be excluded from the impression counts.
• Error handling of an actionType that is not mapped to an ImpressionStorageKey.
• Error logging when frequency cap config is not defined (for when experiment becomes the default path, is not currently reachable by code path).

[oyj9109]

I have a few more comments for nit, but overall looks really great! I love to see how simple the new logic is, yet it is more capable of.

[oyj9109]

LGTM. Thanks for great work!