Fix broken functional tests on TSVB

[sulemanof]

Fix #19471 .
A window size was changed to 1250x600 due to significant inconsistency of a plot rendering in CI browser with local one.
Screenshots were updated due to new size.

• Here is a comparison from CI build when size was 1000x500:

• Then comparePngs func try to compare 2 images with different sizes, and resize them to the same value in px:
  

• It leads to an expected failure (an inconsistency is clearly visible):
  

[elasticmachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request

[alexwizp]

I see that we still have difference between our baseline image and ci image
@vitalics could you please have a look?

[stacey-gammon]

I wonder why ci is passing? Maybe the threshold is too high. It'd be interesting to spit that number out. Honestly though, with the visual testing tools @liza-mae is looking into, I am thinking screenshot testing our own stuff at this point might be a waste of effort.

Liza, do you think the visual testing stuff will cover this kind of screenshot comparisons with our visualizations? I think so... What do you think about just ripping this stuff out?

Just don't rip out anything the reporting stuff needs, since that can't be tested with the visual testing tools.

[liza-mae]

@stacey-gammon yes a visual testing tool can cover this. So we can skip doing it in our current way until we have a tool in place.

[flash1293]

I'm not 100% sure but the current consensus is we don't need this at the moment, so the PR can be closed, right?

[LeeDr]

Please keep this open until the skipped test is either fixed or replaced with a visual testing tool test.

[elasticmachine]

💔 Build Failed

• continuous-integration/kibana-ci/pull-request

[LeeDr]

Actually, it should be an open issue, not this PR. I'll close this and reopen #19471