catchError's error type should be unknown instead of any

[abdulkareemnalband]

In best case scenario catchError's callback's error as parameter should be typed as unknown instead as any
It will force users to handle error more robustly

Its similar to https://www.typescriptlang.org/tsconfig#useUnknownInCatchVariables

But simply changing any to unknown is major breaking change. And we also need a proper plan how to do that

It is not limited to catchError we also need to do the same for retryWhen , subscribe , tap and other operators and functions where we need to work with errors

[kaluginserg]

Previous discussions: #4317, #2646, #6328