[GPU][TRANSFORMATIONS] Support RMS Normalization Fusion without Learnable Affine Parameters (#33861)
### Details:
- This PR enhances RMS normalization fusion to support pattern without
learnable affine parameter (gamma), enabling optimization of transformer
architecture like LTX-Video
- The existing RMS fusion pass only supported pattern with constant
gamma parameter. However, some transformer model (e.g., LTX-Video's
attention layers) use RMS normalization followed by dynamic scaling
operation where the scale factor is non-constant. These pattern was
previously unfused, missing optimization opportunity
- When `elementwise_affine=False` (equivalent to [Pytorch RMS's
attribute](https://docs.pytorch.org/docs/stable/generated/torch.nn.modules.normalization.RMSNorm.html)),
RMS normalization does not include learnable gamma parameters. The gamma
is implicitly fixed to ones, reducing the decomposed graph pattern
from:
`x → Power(2) → ReduceMean → Add(eps) → Sqrt → Divide(1/√) → Multiply(x,
1/√) → Multiply(gamma) `
to:
`x → Power(2) → ReduceMean → Add(eps) → Sqrt → Divide(1/√) → Multiply(x,
1/√) [NO gamma multiplication] `
<img width="648" height="924" alt="image-2026-01-26-22-53-05-973"
src="https://github.com/user-attachments/assets/02b4580f-bbce-43ea-affd-438f0a5f4ea7"
/>
### Tickets:
- [CVS-179953](https://jira.devtools.intel.com/browse/CVS-179953)
---------
Signed-off-by: Andrew Park <andrew.park@intel.com>