Align Codequality MR Widget wording

Follow up Issue from: #374631 (comment 1203886644)

It would be good to align the language between the summary and the badges. Right now we have "improved" and "degraded" in the summary but propose "fixed" and a to-be-determined label for new issues.

• I guess we probably need to start the sentence with "Code quality" (the generic noun for what this feature reports on)
• "Degraded" is kind of an awkward word though I can understand why it was chosen initially
• Possibilities:
  • "Code quality scans found 1 new finding and 2 fixed findings." (don't love "found, findings, findings"
  • "Code quality reports show 1 new finding and 2 fixed findings."
  • "Code quality reports show 1 new and 2 fixed findings."
  • Or swap "resolved" for "fixed", or "problem" for "finding" (though I'd avoid "issue" since that has another meaning).