Add ignorePrometheus Flag for integTest and docTest

[penghuo]

Description

• Added an ignorePrometheus flag to integration and doctest Gradle tasks so Prometheus startup and Prometheus-dependent tests are skipped whenever the property is present (unless explicitly set to false).
• Adjusted doctest harness to drop Prometheus-specific documentation cases when the flag is active.
• Updated developer docs (integration tests, doctest guide, Prometheus datasource section, describe command) to cover the new flag and cross-reference Prometheus metadata guidance.

Testing

./gradlew doctest -DignorePrometheus
./gradlew integTest -DignorePrometheus

Related Issues

Resolves #[Issue number to be closed when this PR is merged]

Check List

• New functionality includes testing.
• New functionality has been documented.
• New functionality has javadoc added.
• New functionality has a user manual doc added.
• New PPL command checklist all confirmed.
• API changes companion pull request created.
• Commits are signed per the DCO using --signoff or -s.
• Public documentation issue/PR created.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[opensearch-trigger-bot]

The backport to 2.19 failed:

The process '/usr/bin/git' failed with exit code 128

To backport manually, run these commands in your terminal:

# Navigate to the root of your repository
cd $(git rev-parse --show-toplevel)
# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add ../.worktrees/sql/backport-2.19 2.19
# Navigate to the new working tree
pushd ../.worktrees/sql/backport-2.19
# Create a new branch
git switch --create backport/backport-4442-to-2.19
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 344af4aa85b0afccfd5903a325aa4423a1afd0e2
# Push it to GitHub
git push --set-upstream origin backport/backport-4442-to-2.19
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/sql/backport-2.19

Then, create a pull request where the base branch is 2.19 and the compare/head branch is backport/backport-4442-to-2.19.

[opensearch-trigger-bot]

The backport to 2.19-dev failed:

The process '/usr/bin/git' failed with exit code 128

To backport manually, run these commands in your terminal:

# Navigate to the root of your repository
cd $(git rev-parse --show-toplevel)
# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add ../.worktrees/sql/backport-2.19-dev 2.19-dev
# Navigate to the new working tree
pushd ../.worktrees/sql/backport-2.19-dev
# Create a new branch
git switch --create backport/backport-4442-to-2.19-dev
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 344af4aa85b0afccfd5903a325aa4423a1afd0e2
# Push it to GitHub
git push --set-upstream origin backport/backport-4442-to-2.19-dev
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/sql/backport-2.19-dev

Then, create a pull request where the base branch is 2.19-dev and the compare/head branch is backport/backport-4442-to-2.19-dev.

[opensearch-trigger-bot]

The backport to 2.19-dev failed:

The process '/usr/bin/git' failed with exit code 128

To backport manually, run these commands in your terminal:

# Navigate to the root of your repository
cd $(git rev-parse --show-toplevel)
# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add ../.worktrees/sql/backport-2.19-dev 2.19-dev
# Navigate to the new working tree
pushd ../.worktrees/sql/backport-2.19-dev
# Create a new branch
git switch --create backport/backport-4442-to-2.19-dev
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 344af4aa85b0afccfd5903a325aa4423a1afd0e2
# Push it to GitHub
git push --set-upstream origin backport/backport-4442-to-2.19-dev
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/sql/backport-2.19-dev

Then, create a pull request where the base branch is 2.19-dev and the compare/head branch is backport/backport-4442-to-2.19-dev.

[penghuo]

Backport PR, #4455