[DOCS] Blocklist follow-up

[joepeeples]

Description

A few tasks to finalize the docs for the blocklist feature:

• Check later builds for any final UI changes, update screenshots as needed.
• Remove preliminary tag coming[8.2.0] from main Blocklist page.
• Mention blocklist/blocked applications in intro to Configure an Endpoint Security integration policy, per [BUG] No mention of the Blocklist tab under the install endpoint page #1873

Notes

• Following up after merging original issue [DOCS] Blocklist #1783 (PR), which we needed to merge earlier to resolve a docs link in [Security solution] [Endpoint] Revisit blocklist wrong labels kibana#128773.