Remove useless pre-generated Pidgin accounts

Which I guess was missed when we removed I2P?

Related, we still pre-generate an OFTC account as well, which seems useless given we have no presence there any more.

Feature Branch: bugfix/16744-remove-useless-pidgin-accounts+force-all-tests

Original created by @anonym on 16744 (Redmine)

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information