[ZEPPELIN-6322] Filter download messages in ProcessData error stream

[celinayk]

What is this PR for?

This PR improves error stream output filtering in the ProcessData class to exclude download-related messages. Currently, Maven/npm download progress information clutters the error stream during integration tests, making it difficult to identify actual errors. This change filters out download messages (e.g., "Downloading:", "Progress: 45%", "1024/2048 KB") while preserving real error messages.

What type of PR is it?

Improvement

Todos

• [x] - Add DOWNLOAD_PATTERNS array with 6 regex patterns
• [x] - Implement isDownloadMessage() method
• [x] - Apply filtering logic in buildOutputAndErrorStreamData()

What is the Jira issue?

ZEPPELIN-6322

How should this be tested?

Screenshots (if appropriate)

Questions:

• Does the license files need to update? No
• Is there breaking changes for older versions? No
• Does this needs documentation? No