Remove 'formerly mcc' from the renamed metrics

[Nereboss]

After deciding to no longer rename the sonar complexity to mcc, we added 'formerly mcc' to it to give users some time to adapt to this big change.

This issue serves as a reminder to remove it in a couple of weeks (probably around end of may).

[Nereboss]

There are two places in the code where the suffix is added (metricChooser.component.html and filderMetricDataByDearchTerm.pipe.ts) and one test (metricChooser.component.spec.ts). Searching for "formerly" in the codebase shows them.