Adds texture and scale randomization event terms

[hapatel-bdai]

Description

• Added back texture randomization event term
• Carrying over texture randomization and scale randomization unit tests from previous PRs
• Added additional replicate physics failure case test

Type of change

• New feature (non-breaking change which adds functionality)

Checklist

• I have run the pre-commit checks with ./isaaclab.sh --format
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• I have updated the changelog and the corresponding version in the extension's config/extension.toml file
• I have added my name to the CONTRIBUTORS.md or my name already exists there

[Mayankm96]

Hmm since "visuals" is something hardcoded, I think it isn't great as we asume asset structure here. Should we make an attribute child_prim_paths and let user specify the exact mesh paths they want to be modifying?

For example:

• For cubes, this will be ["geometry/mesh"]
• For articulations this will be "[body_A/visuals", "body_B/visuals]"

[Mayankm96]

We can combine the two into a single test fixture with the event terms. Might make it easier to add new tests later instead of copying code for just function everytime :)

[Mayankm96]

As discussed with @hapatel-bdai there are few things we need to iron out but since those are NITs at this point, we'll go ahead with merging this MR as we are approaching a code freeze.