added a missing check for the provider key
merged branch fabpot/missing-provider-key-check (PR #7937)

This PR was merged into the 2.1 branch.

Discussion
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added a missing check for the provider key

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | n/a
| License       | MIT
| Doc PR        | n/a

Commits
-------

5b7e1e6 added a missing check for the provider key
added additional tests to cover invalid argument exceptions in OutputFormatterStyle component