Revert pull_request action back

This issue is related to:
- #333
- #334

Status in time of writing this issue is that we are using `pull_request_target` instead of usage `pull_request` in yml files:
- build-scala2.12-spark3.2.yml
- build-scala2.13-spark3.2.yml

This change was needed to be able to merge Approved changes from repository fork.
We were not able to find any better solution in time of change.

Now, when merge is done we are in state where another changes can come inside repository from forks.
It open potential security risk which was solved by simple change configuration for now.
- Configuration change: PR from fork will start GH actions after team member confirmation. This can avoid start of potential dangerous GH action with writing rights.

Fast fix:
- Return back `pull_request` action to both yml files mentioned above.

Slow fix:
- Invite DevOps colleagues into problem solution and do analysis what changes needs to be done.