Removed the "experimental" statement from isaaclab_ov package documentation (isaac-sim#5795)

# Description

Removed the "experimental" statement from isaaclab_ov package
documentation

## Type of change

- Documentation update

## Checklist

- [x] I have read and understood the [contribution
guidelines](https://isaac-sim.github.io/IsaacLab/main/source/refs/contributing.html)
- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./isaaclab.sh --format`
- [x] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] I have updated the changelog and the corresponding version in the
extension's `config/extension.toml` file
- [x] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there

Author: huidongc

source/isaaclab_ov/changelog.d/huidongc-ovrtx-doc-update.rst

@@ -0,0 +1,4 @@
+Changed
+^^^^^^^
+
+* Removed the "experimental" statement from the ``isaaclab_ov`` package documentation.

source/isaaclab_ov/docs/README.md

@@ -2,5 +2,3 @@
 
 This extension provides Omniverse renderers for tiled camera rendering in Isaac Lab,
 including OVRTX for RTX-based path tracing without requiring Isaac Sim.
-
-OvRTX is an experimental rendering backend.