Add option to clear TextPrompt after input

[ThePCJakub]

fixes #1154

• I have read the Contribution Guidelines
• I have commented on the issue above and discussed the intended changes
• A maintainer has signed off on the changes and the issue was assigned to me
• All newly added code is adequately covered by tests
• All existing tests are still running without errors
• The documentation was modified to reflect the changes OR no documentation changes are required.

Changes

• Add a ClearOnFinish property to TextPrompt<T> to optionally clear the prompt line after successful input.
• Add a ClearOnFinish() fluent extension for easier configuration.
• Clear the prompt line by emitting an ANSI clear-line sequence (ESC[2K) when ANSI is supported.
• Add an expectation-based test (ClearOnFinish) to verify the output of TextPrompt<string> with ClearOnFinish() enabled.

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