Example Tags: Add tags for example with GPU stats panel

[gkjohnson]

Related issue: #21509

Description

Add tags related to the GPU stats panel for the webgl_lines_fat example to make it more discoverable.

[WestLangley]

Hmmm. That example does not need an animation loop. Perhaps a different example would be a better choice?

[gkjohnson]

The GPU stats panel doesn't require a constantly running animation loop -- internally it continues to check on subsequent frames specifically so the on-demand rendering use case works without issue. And I chose the line_fat example because (at least on my lower end laptop) you can see GPU time differences when adjusting the material parameters. It consistently goes from 1ms to 2ms on my 2017 MS Surface Laptop when moving the line width between extremes. The GPU time would probably vary more if you could make the lines thicker. If there's another example you recommend that can easily toggle between intensive and less intensive in terms of GPU work I can add it there, too.

Also as noted here I would still like to increase the decimal precision of the displayed number so the affect of the material changes are more apparent, but that's for another PR.