Fixing configuration validation error messages.

The min and max validation functions lead to incorrect error messages.
merged branch seiffert/master (PR #8465)

This PR was submitted for the master branch but it was merged into the 2.2 branch instead (closes #8465).

Discussion
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[Config] Fixed error messages of min/max validation methods

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

This PR fixes the error messages of the configuration validation methods `min` and `max`. The error message was "Should be greater/less than: <value>" but should be "Should be greater/less than or equal to <value>".

Commits
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3395837 Fixing configuration validation error messages.