metrics filters: improve handling when nothing matches the filters

[valentijnscholten]

One the Product Type and Product metrics there was an error message when no findings or endpoints matched the selected filters. The metrics would fallback to show "all findings/endpoints",

This PR:

• Removes the fallback and just shows empty metrics
• Changes the message to inform the user

[sc-11515]

Funny thing is the existing test case to test the endpoints metrics was using a filter based on current month. This results in no endpoints matching the filter because the testdata is 5 years old. But the old DD code did a fallback to return all endpoints, making the test pass. This PR now mocks now and fixes the test properly.

Testing: I don't think all metrics cases have test coverage, so a "click through" test by someone knowledgable about metrics should be done.

Question: Should we just remove the message? Most other metrics/filtering pages don't show this message.

[dryrunsecurity]

No security concerns detected in this pull request.

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All finding details can be found in the DryRun Security Dashboard.

[Maffooch]

Question: Should we just remove the message? Most other metrics/filtering pages don't show this message.

I think we should keep it. It is a weird user experience to click the metrics button, and then see zero findings reported if all of them are older than 30 days. The message provides a good hint of where to look for next steps

[mtesauro]

Approved