Promote the Dockerfile, Docker Compose, and Helm Detectors to Experimental Status

[jpinz]

This pull request updates the status of the Docker Compose, Dockerfile, and Helm component detectors from "DefaultOff" to "Experimental" across both documentation and code. As a result, these detectors now run automatically during scans, but their output is not included in the final scan results. The changes also update the documentation to reflect the new "Experimental" status and clarify how these detectors behave.

Example Run with Detectors Enabled
Components were successfully registered

[Copilot]

Pull request overview

This PR promotes the Dockerfile, Docker Compose, and Helm detectors from DefaultOff to Experimental so they run by default during scans (with results excluded from the final scan output unless explicitly enabled), and updates detector documentation to reflect the new status.

Changes:

• Update Helm, Dockerfile, and Docker Compose detector implementations to implement IExperimentalDetector instead of IDefaultOffComponentDetector.
• Update detector documentation pages to describe the new Experimental behavior.
• Update the detectors README status tables to mark these detectors as Experimental.

Show a summary per file

File	Description
src/Microsoft.ComponentDetection.Detectors/helm/HelmComponentDetector.cs	Switch Helm detector to IExperimentalDetector.
src/Microsoft.ComponentDetection.Detectors/dockerfile/DockerfileComponentDetector.cs	Switch Dockerfile detector to IExperimentalDetector.
src/Microsoft.ComponentDetection.Detectors/dockercompose/DockerComposeComponentDetector.cs	Switch Docker Compose detector to IExperimentalDetector.
docs/detectors/helm.md	Update Helm detector status/behavior text to Experimental.
docs/detectors/dockerfile.md	Update Dockerfile detector status/behavior text to Experimental.
docs/detectors/dockercompose.md	Update Docker Compose detector status/behavior text to Experimental.
docs/detectors/README.md	Mark the three detectors as Experimental in the status tables.

Copilot's findings

Comments suppressed due to low confidence (3)

docs/detectors/dockerfile.md:29

• Known limitations mentions experimental output suppression but doesn’t mention the opt-in path to include results. Please add guidance on using --DetectorArgs DockerReference=Enable (or EnableIfDefaultOff) to include output when needed.

- **Experimental Status**: This detector runs automatically but its output is not included in scan results

docs/detectors/dockercompose.md:45

• Known limitations should mention how to opt-in to include detector output (e.g., --DetectorArgs DockerCompose=Enable / EnableIfDefaultOff), otherwise users have no documented way to get results from an experimental detector.

- **Experimental Status**: This detector runs automatically but its output is not included in scan results

docs/detectors/helm.md:48

• Similar to the overview section, the Known limitations entry says experimental output is not included, but doesn’t explain how to opt-in to include results. Please add a note that passing --DetectorArgs Helm=Enable (or EnableIfDefaultOff) will treat it as a normal detector and include its output.

- **Experimental Status**: This detector runs automatically but its output is not included in scan results

• Files reviewed: 7/7 changed files
• Comments generated: 3