Update delete integration test

[MichelHollands]

What this PR does / why we need it:

Update the deletion integration test so it waits until the delete request has been processed. Note that at the moment no lines are removed due to flush not working. This will be fixed later on in a separate PR.
Add a metric to show how many lines are deleted.
Remove mention of Cortex in a helper function.
Change the various timeouts so the test runs in 10 seconds.
Add code to parse and check metrics.

Checklist

• Documentation added
• Tests updated
• Is this an important fix or new feature? Add an entry in the CHANGELOG.md.
• Changes that require user attention or interaction to upgrade are documented in docs/sources/upgrading/_index.md

[grafanabot]

./tools/diff_coverage.sh ../loki-main/test_results.txt test_results.txt ingester,distributor,querier,querier/queryrange,iter,storage,chunkenc,logql,loki

Change in test coverage per package. Green indicates 0 or positive change, red indicates that test coverage for a package fell.

+           ingester	0%
+        distributor	0%
+            querier	0%
+ querier/queryrange	0%
+               iter	0%
+            storage	0%
+           chunkenc	0%
+              logql	0%
+               loki	0%

[MasslessParticle]

This looks awesome

[grafanabot]

./tools/diff_coverage.sh ../loki-main/test_results.txt test_results.txt ingester,distributor,querier,querier/queryrange,iter,storage,chunkenc,logql,loki

Change in test coverage per package. Green indicates 0 or positive change, red indicates that test coverage for a package fell.

+           ingester	0%
+        distributor	0.3%
+            querier	0%
+ querier/queryrange	0%
+               iter	0%
+            storage	0%
+           chunkenc	0%
+              logql	0%
+               loki	0%

[trevorwhitney]

This looks great! LGTM

[grafanabot]

./tools/diff_coverage.sh ../loki-main/test_results.txt test_results.txt ingester,distributor,querier,querier/queryrange,iter,storage,chunkenc,logql,loki

Change in test coverage per package. Green indicates 0 or positive change, red indicates that test coverage for a package fell.

+           ingester	0%
+        distributor	0.3%
+            querier	0%
+ querier/queryrange	0%
+               iter	0%
+            storage	0%
+           chunkenc	0%
+              logql	0%
+               loki	0%

[chaudum]

nit: since newErr is used nowhere else ...

Suggested change

	newErr := fmt.Errorf("error starting component %v: %w", c.name, err)
	errCh <- newErr
	errCh <- fmt.Errorf("error starting component %v: %w", c.name, err)

[grafanabot]

The backport to k102 failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new branch
git switch --create backport-6192-to-k102 origin/k102
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x 65e3148bc97159a2efaefdc0bcc5e2fa88c40870
# Push it to GitHub
git push --set-upstream origin backport-6192-to-k102
git switch main
# Remove the local backport branch
git branch -D backport-6192-to-k102

Then, create a pull request where the base branch is k102 and the compare/head branch is backport-6192-to-k102.