431: Update teacher not found message

[edujackedu]

Update the error message to tell the users what to do if teacher is not found

[peteryates]

This error is kind of shared between the TRN and the DOB, I think the error should include both field name. The link on the error summary probably should still go to the TRN field though so I think it should remain on :trn rather than :base.

Also the tone of the language here isn't quite right in my opinion, words like 'Please' are avoided.

Maybe:

Suggested change

	raise(
	TRS::Errors::TeacherNotFound,
	"Teacher with TRN #{trn} not found. Please liaise with the ECT to confirm their DOB and TRN or contact support"
	)
	raise(
	TRS::Errors::TeacherNotFound,
	"No teacher with the provided teacher reference number and date of birth was found"
	)

Additionally it might be a good idea to separate the raised error text from the error text we add to the object, as it would be useful to get the incorrect TRN/DOB in there (I suspect it's not PII if it's invalid?) In that case the above text can go in the rescue in the controller.

I think the guidance on contacting support if the details entered look right but don't match anything should either go in a hint or in a paragraph above between the page heading and the TRN field. We can use the design in #430 as a starting off point, but the hint text doesn't work for us because the AB (probably) won't have the payslip or reg documents from GTCE.

Find your ECT by entering their teacher reference number (TRN) and date of birth. If you can't find them contact support.