doc: Add troubleshooting for coverage error statuses CY-6365

[prcr]

Adds a troubleshooting table for the possible coverage "error status" displayed on the coverage set-up page for each repository:

• Commit not found
• Branch not enabled
• Commit not analyzed
• Pending

:eyes: Live preview

https://github.com/codacy/codacy-coverage-reporter/blob/doc/add-error-status-troubleshooting-CY-6365/docs/troubleshooting-common-issues.md#error-status

:construction: To do

• [ ] Merge https://github.com/codacy/codacy-coverage-reporter/pull/406 and https://github.com/codacy/codacy-coverage-reporter/pull/407
• [ ] Move the troubleshooting table to the final location and link it from the setup validation section