RedisCache lost support for function as a key_prefix

[dbascoules]

Bug description

The hability to specify a function as a key_prefix for RedisCache doesn't work anymore in Superset. Expected type 'str', got '() -> str' instead error is thrown.

This was fundamental for my usecase where I use the subdomain of the Superset URL as an ingredient of my PostgreSQL RLS. Each subdomain correspond to a subset of the data that users may query through Superset (only one instance).

Introducing the notion of subdomain in the Redis cache key prefix avoids a cache mismatch between subdomains and data subsets. It's implemented with a function parametrized in RedisCache key_prefix.

I submitted a PR in the concerned lib project : pallets-eco/cachelib#332.

How to reproduce the bug

1. Create a simple function returning a string.
2. Parameter this function in the RedisCache key_prefix.
3. Display in Superset anything related to your data that will be cached to throw the error.

Screenshots/recordings

No response

Superset version

3.0.3

Python version

3.11

Node version

Not applicable

Browser

Not applicable

Additional context

`Expected type 'str', got '() -> str'

Checklist

• [X] I have searched Superset docs and Slack and didn't find a solution to my problem.
• [X] I have searched the GitHub issue tracker and didn't find a similar bug report.
• [X] I have checked Superset's logs for errors and if I found a relevant Python stacktrace, I included it here as text in the "additional context" section.