Give an explanation for NO_LCP when content is all canvas/SVG

Another person ran into #11326: https://twitter.com/FredKSchott/status/1376606554061893633

But currently the error we give is "Something went wrong with recording the trace over your page load. Please run Lighthouse again. (`NO_LCP`)". In this case, running Lighthouse again will not produce a better result the second time.

I'm not sure if there's anything we can do for the null perf score as long as we require LCP and LCP is defined the way it is (https://github.com/WICG/element-timing/issues/47, https://github.com/WICG/element-timing/issues/56), but we can at least let the user know what's happening.

Hand waving the heuristics here, but if
- there's no LCP
- there is painted content
- all of that content is SVG or canvas

we should give a custom `NO_LCP` error to let them know the reason for the null score.

related: #11326

Start by tracing where the NO_LCP error is generated and review related issue #11326. Confirm how Lighthouse identifies painted content and whether it is all SVG or canvas; done means this case receives an explanatory NO_LCP message instead of asking the user to rerun Lighthouse.

Written by the indexing model from the issue text.