add error to Transition Overlay if error occurs when changing wallet from BTC -> BAT

[LaurenWags]

Description

BTC --> BAT wallet is taking more time than expected during QA (30-40+ minutes). Per discussions, if an error occurs during this process we should display this error on the transition overlay/progress screen. TBD: wording for this and if we show generic error or raw error. cc @davidtemkin @bsclifton @NejcZdovc

Steps to Reproduce

Actual result:
If error occurs, there isn't an indication on the transition overlay.

Expected result:
Error to be displayed, text and what kind of error are TBD.

Reproduces how often: [What percentage of the time does it reproduce?] unknown

Brave Version

about:brave info:
Brave | 0.19.43
rev | 24df93d
Muon | 4.4.27

Reproducible on current live release:
n/a

Additional Information

[bsclifton]

moving to 0.19.x release 2- for the time being, we can advise folks to run command line with LEDGER_VERBOSE=true and share logs. In order to handle this issue properly, we'd need a decision on what text to show (above) and we'd need to know how it should look
cc: @bradleyrichter @davidtemkin

[cezaraugusto]

adding needs-info as this requires input from outside engineering team

[bsclifton]

@bradleyrichter is this issue sufficiently addressed by putting "Loading..." in the address field? (see #11771)

[bsclifton]

Moving out from milestone 😄 We'll need to solve this. I'll assign myself and document possible error states so that we can create mock ups

[bsclifton]

Without specific examples, here are the main use-cases we can create a generic message for:

• can't reach server (internet is down, etc)
• a very specific error is returned from eyeshade (probably not something we want to display as-is)
• a generic 422 or 503 error is returned (server is busy / unprocessable)

[bsclifton]

cc: @alexwykoff @bradleyrichter @jenn-rhim for mockup

[NejcZdovc]

close it as won't fix, because we should be good now