Optional failure for a tile that is already staged

[jhvhs]

• A short explanation of the proposed change:

Provide a flag that prevents false positives on the tile upgrade.

• An explanation of the use cases your change solves:

When a tile has an upgrade pipeline, but the version has been updated manually for some reason, the pipeline would keep failing until a new version of the tile is published.

• Expected result after the change:

When the operator sets the SKIP_IF_ALREADY_STAGED param for the stage-tile job to yes, and the latest matching tile version matches the version of the tile that has been manually installed, the upgrade pipeline does not fail, and does not attempt the upgrade.

• Current result before the change:

When the newest available matching tile version coincides with the version currently installed, the pipeline would invariably fail.

• Links to any other associated PRs or issues:

• [x] I have viewed signed and have submitted the Contributor License Agreement

• [x] I have made this pull request to the master branch

• [x] I have run all the unit tests

[cf-gitbot]

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