Improve WebGL disabled error

[meiqimichelle]

Right now it says:

We could be more helpful with next steps, such as checking if webGL is disabled: https://get.webgl.org/webgl2/

Note: the relevant text is at wwwroot/languages/en/translation.json line 707 but do not search for "Terria Digital Twin" -- it has a template variable {{appName}}.

Also note: may want to have a look at these two messages together, to make sure they both are correct >>>

slowWebGLAvailableMessageII suggests slow-but-available WebGL, but it's actually used when Cesium completely fails to initialize [this ticket]. There's a separate slowWebGLAvailableMessage (line 706 in the translation file) that's never referenced from this catch block.

[AnaBelgun]

In case users have their WebGL disabled in Chrome, we could add some useful tips in the error message, mainly for convenience (ie. no need to search on how to fix it):

Here are a few ways to re-enable WebGL2 in Chrome:

1. Enable via Chrome Flags (most common fix)

Open a new tab and go to chrome://flags
Search for "WebGL"
Set "WebGL 2.0" to Enabled
Click Relaunch to restart Chrome

2. Check Hardware Acceleration

Go to chrome://settings
Search for "hardware acceleration"
Make sure "Use graphics hardware acceleration when available" is turned on
Relaunch Chrome