Custom domains: update TLS cert and key info

[brentschaus-okta]

Description:

• What's changed? Okta now supports TLS certs and keys of 2048, 3072, and 4096 bits
• Is this PR related to a Monolith release? Yes. 2024.08.0

Resolves:

• OKTA-746721

[acrolinxdevdocs-okta]

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Article	Total score Required:80	Word and phrases (Brand, terms) Preferred: 80	Correctness (Spelling, grammar) Preferred: 80	Clarity (Readability) Preferred: 80	Inclusive language (+ accesibility) Preferred: 80
:white_check_mark: packages/@okta/vuepress-site/docs/guides/custom-url-domain/main/index.md	82	86	83	61	99

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[eng-info-dev-github-bot]

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