W-24105067: Document 25-character egress rule group name limit

[kevintroller]

Summary

• Updates the custom egress rule group name constraints on ps-config-app-level-egress.adoc.
• Replaces the stale combined-length rule (generated <private_space_name>-<rule_group_name> ≤ 53 characters) with the standalone 25-character Name limit and letters/numbers/hyphens only.
• Resolves W-24105067.

Requested change vs. what landed

Ticket request	Status
Name field max 25 characters	Documented on Create a new custom egress rule group
Pattern ^[a-zA-Z0-9-]+$ (letters, numbers, hyphens)	Documented in plain language (no regex in the page)
Remove previous combined-length ≤ 52/53 rule	Removed (<private_space_name>-<rule_group_name> ≤ 53 characters)

Style applied

Active voice, contractions, and no the following. The regex is described as “letters, numbers, and hyphens” to match surrounding CX style.

Sources

• GUS W-24105067 — the doc request (25-character limit, allowed characters, page URL).
• GUS W-23579934 — closed API change that introduced the restriction (fix for W-21654859).

Open decisions for review

• Confirm existing rule groups with spaces or names longer than 25 characters are out of scope for this page (the ticket describes the new create/rename constraints only).
• The previous 53-character combined firewall name isn’t restated. If that generated-name cap still exists alongside the 25-character Name field, say so and we can add it back.

Test plan

• Preview ps-config-app-level-egress.adoc and confirm the Create Rule Group step no longer mentions 53 characters.
• Confirm the Name field in Runtime Manager matches: max 25, letters/numbers/hyphens only.