Fixed #9435 -- Redirected the root URL of a project if APPEND_SLASH is set.

[avallbona]

9435 new [Bug] - Checked out behaviour of wsgi backend with PATH_INFO being an empty string.

Redirecting the root URL of a project if APPEND_SLASH is set
(following work from old pr #7663)

Trac ticket number

ticket-9435

Branch description

Provide a concise overview of the issue or rationale behind the proposed changes.

Checklist

• This PR targets the main branch.
• The commit message is written in past tense, mentions the ticket number, and ends with a period.
• I have checked the "Has patch" ticket flag in the Trac system.
• I have added or updated relevant tests.
• I have added or updated relevant docs, including release notes if applicable.
• I have attached screenshots in both light and dark modes for any UI changes.

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