Decrease reporting threshold for snapshot comparisons

[stacey-gammon]

Due to #21485 we had to bump the reporting threshold comparison higher.

In order to turn reporting snapshot tests on asap, we bumped the threshold higher to account for it. This will lead to more false passes, so we should either fix the bug (probably not going to happen), take phantom specific baselines (more effort than it's worth?) or just wait till we deprecate phantom, then drop our phantom reporting tests and drop the threshold down once we are only comparing on chromium.

Given time and priorities, I'm guessing we are going to end up with the last option.

[tsullivan]

Note, as of this writing, it looks like all of the tests that compare images are disabled. They would be in test/reporting/functional/reporting.js and use the checkIfPdfsMatch, checkIfPngsMatch functions.

[elasticmachine]

Pinging @elastic/kibana-reporting-services (Team:Reporting Services)

[tsullivan]

Tests are re-enabled now as of #46076

I think I prefer keeping the threshhold as high as it needs to be, to keep them on. Even with a high threshhold, we still have a lot of benefits of automation:

• make sure that Reporting integration didn't suddenty break because of DOM refactoring
• make sure the PDF ends up with the expected number of pages
• make sure the page is showing an actual Kibana App, not something such as an error screen

@joelgriffith thoughts?

[elasticmachine]

Pinging @elastic/kibana-app-services (Team:AppServices)

[tsullivan]

The threshold has been lowered in #87600 so that the percentage of difference should be lower than 0.09