Remove blocks-storage.tsdb.isolation-enabled option.

[pstibrany]

What this PR does

This PR removes -blocks-storage.tsdb.isolation-enabled option, which defaulted to false. For rationale see #1655.

Checklist

• [na] Tests updated
• [na] Documentation added
• CHANGELOG.md updated - the order of entries should be [CHANGE], [FEATURE], [ENHANCEMENT], [BUGFIX]

[pracucci]

LGTM but please add a CHANGELOG entry. We previously announced the deprecation, now we should mention the removal.

[pstibrany]

LGTM but please add a CHANGELOG entry. We previously announced the deprecation, now we should mention the removal.

There is a changelog entry, right? 🤔

[pracucci]

🙈

[grafanabot]

The backport to release-2.3 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-2782-to-release-2.3 origin/release-2.3
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x bf018089f2c8c5f31b483c056494b9e24606bc48
# Push it to GitHub
git push --set-upstream origin backport-2782-to-release-2.3
git switch main
# Remove the local backport branch
git branch -D backport-2782-to-release-2.3

Then, create a pull request where the base branch is release-2.3 and the compare/head branch is backport-2782-to-release-2.3.