[8.x] [Feature Flags Example Plugin] Change ctx provider (#201097)

[gsoldevila]

Backport

This will backport the following commits from main to 8.x:

• [Feature Flags Example Plugin] Change ctx provider (#201097)

Questions ?

Please refer to the Backport tool documentation

[elasticmachine]

:green_heart: Build Succeeded

• Buildkite Build
• Commit: 3d541f62c216e7dca449b05ca2ab96e1b2e93331

Metrics [docs]

✅ unchanged