Update generate_samples in LK and LGPU to support qml.measurements.Shots

[maliasadi]

Context: PR https://github.com/PennyLaneAI/pennylane/pull/6046 wraps the legacy device API automatically in various device creation, qnode, and execute functions. As LK and LGPU plugins still rely on the legacy device API, the shots tests and the generate_samples logic in lightning_kokkos.py and lightning_gpu.py should be updated to adhere the new convention.

Related Shortcut Stories: [sc-65998]

[github-actions[bot]]

Hello. You may have forgotten to update the changelog! Please edit .github/CHANGELOG.md with:

• A one-to-two sentence description of the change. You may include a small working example for new features.
• A link back to this PR.
• Your name (or GitHub username) in the contributors section.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 75.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 81.65%. Comparing base (83ac9d8) to head (17d9912). Report is 83 commits behind head on master.

Files with missing lines	Patch %	Lines
...ane_lightning/lightning_kokkos/lightning_kokkos.py	0.00%	1 Missing :warning:

:exclamation: There is a different number of reports uploaded between BASE (83ac9d8) and HEAD (17d9912). Click for more details.

HEAD has 52 uploads less than BASE

| Flag | BASE (83ac9d8) | HEAD (17d9912) | |------|------|------| ||60|8|

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #839 +/- ## =========================================== - Coverage 98.33% 81.65% -16.68% =========================================== Files 113 17 -96 Lines 18741 1930 -16811 =========================================== - Hits 18429 1576 -16853 - Misses 312 354 +42 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

---

🚨 Try these New Features:

• Flaky Tests Detection - Detect and resolve failed and flaky tests