fix(post): post creation interactions [MOSOWEB-46]

[jpezninjo]

MOSOWEB-46 https://mozilla-hub.atlassian.net/browse/MOSOWEB-46

Goal

All post creations, replies and edits should have an analytics action associated.

Send the following Engagement Event:

engagement event
ui_identifier is post.create (or something like that)
Includes a mastodon_status_id that we can cross-reference against prod data
engagement_type is post

I'd love feedback/perspectives on:

• Do I buy Lego 10305 - Lion Knights' Castle? Non-Star Wars building sets are suddenly really enticing to me.

Implementation Decisions

• The oddball in the list of new events, home.post.create, is a decision from Kirill

New analytics events

• home.post.create
• post.create
• post.edit
• post.reply

[anthony-liddle]

This nested ternary makes me sad but I get the necessity of it