[8.16](backport #4087) Update version of elastic/ec terraform provider to latest

[mergify]

What it says on the tin.

https://registry.terraform.io/providers/elastic/ec/0.12.1

---

This is an automatic backport of pull request #4087 done by Mergify.

[mergify]

Cherry-pick of daafd1a has failed:

On branch mergify/bp/8.16/pr-4087
Your branch is up to date with 'origin/8.16'.

You are currently cherry-picking commit daafd1a.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   dev-tools/cloud/terraform/main.tf

no changes added to commit (use "git add" and/or "git commit -a")

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[elastic-sonarqube]

Quality Gate passed

Issues
0 New issues
0 Fixed issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
No data about Duplication

See analysis details on SonarQube