Specify that VUID-RuntimeSpirv-x-06432 applies only to compute shaders

[Rua]

Both VUID-RuntimeSpirv-TaskEXT-07294 and VUID-RuntimeSpirv-MeshEXT-07298 specify that the requirement only applies to task and mesh shaders, respectively, but VUID-RuntimeSpirv-x-06432 does not specify that it applies only to compute shaders. Since maxComputeWorkGroupInvocations is defined elsewhere as

the maximum total number of compute shader invocations in a single local workgroup

this seems like an omission. This PR adds it, using the first two VUIDs as a template.

I've also given the same treatment to VUID-RuntimeSpirv-x-06429, VUID-RuntimeSpirv-x-06430 and VUID-RuntimeSpirv-x-06431, regarding the maxComputeWorkGroupSize limit.

[oddhack]

@spencer-lunarg please take a look.

[spencer-lunarg]

LGTM - This is just making the VU wording consistent with the Mesh/Task shaders VUs

[oddhack]

LGTM - This is just making the VU wording consistent with the Mesh/Task shaders VUs

OK. I think we can just sign it off for the next spec update, then.