fix: Fix error message for non nullable converter

[ValentinVignal]

Fixes #2854

[simolus3]

Thanks!

[ValentinVignal]

I quickly looked around and wasn't able to find if you have already written some tests for reported errors.

Where / how do you want me to write a test for that?

[simolus3]

I think this assertion just needs to be expanded to cover the full message:

drift/drift_dev/test/analysis/resolver/dart/type_converter_test.dart

Lines 85 to 86 in 261c151

	isDriftError(contains('This column is nullable'))
	.withSpan('tc<String?, String>()'),

[ValentinVignal]

Thank you @simolus3 , I implemented a test in test: Update the tests