Allow TF plan checks to run on forks PRs, add concurrency to parallel E2Es

[Zvikan]

What does this PR do?

• Adds concurrency to E2Es workflows (parallel apply & destroy)
• Sets TF plan to use pull_request_target and use GitHub environment.

Motivation

• concurrency to prevent from multiple TF apply/destroy run on the same time as the state is the same - https://docs.github.com/en/actions/using-jobs/using-concurrency

• Allows PRs from forks to run against TF plan checks by allowing pull_request_target to be used while utilizing GitHub Environment to prevent "pwn request", allowing humans (repo code owners) to review the PRs and deploy relevant checks when it's safe to do so.

More

• Yes, I have tested the PR using my local account setup (Provide any test evidence report under Additional Notes)
• Yes, I have added a new example under examples to support my PR
• Yes, I have created another PR for add-ons under add-ons repo (if applicable)
• Yes, I have updated the docs for this feature
• Yes, I ran pre-commit run -a with this PR

Note: Not all the PRs required examples and docs except a new pattern or add-on added.

For Moderators

• E2E Test successfully complete before merge?

Additional Notes