[4.0] Consistent validation of the database name

[wilsonge]

com_config is looser at validating the database name than the installer (which was patched as part of #23704). This should be normalised using a standard validation filter for JForm

[joomdonation]

From what I see, that kind of validation is nice to have but not needed anymore. The reason is because before the change is saved, we even try to connect to database to see if it works before saving the change.

With that said, I'm closing this issue for now. Please re-open it if you still want to have this validation rule implemented.

[wilsonge]

I do want it because it's more about the security of what we are validating before trying to connect than whether it works or not

[alikon]

plesase test #39889

[richard67]

Closing as having a pull request. Please test #44623 . Thanks in advance.