[Bugfix] Support parsing chat prompt if role property has \r around colon

[chjinche]

Description

Issue:

UX may add extra '\r' to user input, which may throw confusing error to user because user does not write '\r' explicitly.

• user input
  

• ux adding extra '\r'
  

• confusing error
  

Solution:

Handling '\r' around role property colon. The same way as '\r' around role colon.

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.
• Create an issue and link to the pull request to get dedicated review from promptflow team. Learn more: suggested workflow.

General Guidelines and Best Practices

• Title of the pull request is clear and informative.
• There are a small number of commits, each of which have an informative message. This means that previously merged commits do not appear in the history of the PR. For more information on cleaning up the commits in your PR, see this page.

Testing Guidelines

• Pull request includes test coverage for the included changes.