Fix the installer test issues

[nandajavarma]

Description

The newly merged changes has some flaws that were caught a bit late. These are the changed I am making as a part of this PR:

• The Azure DNS records take longer to propagate and hence need a longer sleep time
• Escaping was missing around db password on Azure
• This was caught due to the registry pre-flights, but I had missed a small change during a merge conflict resolution. The registry password for GCP is not the base64 of the service account JSON, but the string version of it. Fixed it with this PR.

Related Issue(s)

Fixes #

How to test

From a workspace opened from this PR having core-dev cluster access, you can run one of the following:

 werft run github -a cluster=aks -a skipTests=true -a deps=external -j .werft/self-hosted-installer-tests.yaml 
 werft run github -a cluster=gke -a skipTests=true -a deps=external -j .werft/self-hosted-installer-tests.yaml 

Release Notes

NONE

Documentation

Werft options:

• /werft with-preview