prompty: adds embeddings api support

[ianchi]

Description

The capabilities of Prompty model definition and templating are also usefull to interfase with embeddings
Adds api = 'embedding' option to be able to use it in the same fashion

All Promptflow Contribution checklist:

• The pull request does not introduce [breaking changes].
• CHANGELOG is updated for new features, bug fixes or other significant changes.
• I have read the contribution guidelines.
• I confirm that all new dependencies are compatible with the MIT license.
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• Title of the pull request is clear and informative.
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Testing Guidelines

• Pull request includes test coverage for the included changes.

[github-actions]

Hi, thank you for your interest in helping to improve the prompt flow experience and for your contribution. We've noticed that there hasn't been recent engagement on this pull request. If this is still an active work stream, please let us know by pushing some changes or leaving a comment.

[ianchi]

Hi, any chance to advance with this?

[github-actions]

SDK CLI Global Config Test Result embedding

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Results for commit a25ae15.

[github-actions]

Executor Unit Test Result embedding

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Results for commit a25ae15.

[github-actions]

Executor E2E Test Result embedding

0 tests   0 ✅  0s ⏱️
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0 files    0 ❌

Results for commit a25ae15.