Use randomAlphanumeric instead of random for password in tests codes

[pmverma]

Follow up of #18502

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• Tests are added where necessary
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[pmverma]

It is strange that I am not able to reproduce the failing build locally.

@DanielFran , Can you please help follow the steps to reproduce?

1. Run mkdir pr18530 && cd pr18530 && touch .yo-rc.json
2. Copy .yo-rc.json of failing build
3. Remove entities from .yo-rc.json
4. Run jhipster
5. Run ./mvnw clean verify

Failing error log is strange.
I need to check for the string literal "test", it is defined nowhere in the file.

[DanielFran]

@pmverma I did the test this morning and was not able to reproduce it locally also :(

Maybe something related with ci-cd cache?
@mshima any clue?

[mshima]

My guess would be that the cleanup failed.
I added a change to test.

[mshima]

It is a leftover from UserJWTControllerIT test.
Don't know why it started failing with this PR.