Clean statement descriptor value before saving it

[cesarcosta99]

Description

This is a follow-up issue that came out of this discussion. We should consider to clean the statement descriptor values before saving them in the settings. That would increase confidence that the data would not make the intents fail and we would not have to clean every time we send them.

Acceptance criteria

• It errors when trying to save it with disallowed characters.
• It applies to both full bank statement and shortened bank statement (the latter is still in process of being released, at the time of writing – see [Settings] Add shortened customer bank statement #3625).
• Remove cleaning processes where the statement descriptor is being sent to the intent, if they exist (you can look for occurrences on Send bank statement descriptors to payment intents #3643).

Dev notes

See this Stripe's method as a reference – it should not be entirely copied because it probably doesn't match our needs.

Currently the validation is accepting values like " testing" without errors. In cases like that, we can either make the validation stricter – ideally it would be as strict as it requires, like not accepting any spaces – or trimming it before saving it, which I'd not recommend because that would require us to reflect that change in the UI.