ci(integration): use new args for re-usable Helm integration test

[ev-codes]

Description

The Helm integration test workflow we rely on (test-integration-template.yaml) and camunda-platform-helm as a whole was recently refactored to rely on directories instead of branches for chart versions. See issue for more context

This PR passes in the new required arguments. It also updates variable names and documentation to reflect the new directory system.

Test Runs

To help reviewers understand the changes, here's a test run of this workflow that @ev-codes ran against Connectors v8.3.11

Related issues

closes https://github.com/camunda/team-connectors/issues/804

[github-actions[bot]]

Backport failed for release/8.3, because it was unable to cherry-pick the commit(s).

Please cherry-pick the changes locally and resolve any conflicts.

git fetch origin release/8.3
git worktree add -d .worktree/backport-2728-to-release/8.3 origin/release/8.3
cd .worktree/backport-2728-to-release/8.3
git switch --create backport-2728-to-release/8.3
git cherry-pick -x e2f22ff055371699c1c2616bfcb2dd577217c190

[github-actions[bot]]

Backport failed for release/8.4, because it was unable to cherry-pick the commit(s).

Please cherry-pick the changes locally and resolve any conflicts.

git fetch origin release/8.4
git worktree add -d .worktree/backport-2728-to-release/8.4 origin/release/8.4
cd .worktree/backport-2728-to-release/8.4
git switch --create backport-2728-to-release/8.4
git cherry-pick -x e2f22ff055371699c1c2616bfcb2dd577217c190

[github-actions[bot]]

Backport failed for release/8.5, because it was unable to cherry-pick the commit(s).

Please cherry-pick the changes locally and resolve any conflicts.

git fetch origin release/8.5
git worktree add -d .worktree/backport-2728-to-release/8.5 origin/release/8.5
cd .worktree/backport-2728-to-release/8.5
git switch --create backport-2728-to-release/8.5
git cherry-pick -x e2f22ff055371699c1c2616bfcb2dd577217c190

[github-actions[bot]]

Successfully created backport PR for release/8.6:

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