Move SAML troubleshooting to separate page

What does this MR do?

Reorganizes SAML troubleshooting content from both self-managed page and SaaS page to a single page as proposed in #363811 (closed).

Notes:

• I decided to leave SCIM alone for now since that feature is not yet in self-managed.
• I attempted to focus on the reorganization and only do minimal updates to content to make it relevant for both SM and SaaS.
• One section I moved to the main SaaS SAML page because it should've been there.
• Merged/removed a couple of redundant or outdated troubleshooting sections.
• Tier badging on headings in troubleshooting is unusual but felt like the easiest way to mark if something was only relevant to SM or SaaS.

Related issues

Resolves #363811 (closed).

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