SharePoint Server connector - API Call for files updated

[OatMilky]

API call for files updated

Updated the API call for files to getFileByServerRelativePath, because its the more modern method and fixes the problem that files with special character like #, %, ' can be crawled too.

Checklists

Pre-Review Checklist

• this PR does NOT contain credentials of any kind, such as API keys or username/passwords (double check config.yml.example)
• this PR has a meaningful title
• this PR links to all relevant github issues that it fixes or partially addresses
• if there is no GH issue, please create it. Each PR should have a link to an issue
• this PR has a thorough description
• Covered the changes with automated tests
• Tested the changes locally
• Added a label for each target release version (example: v7.13.2, v7.14.0, v8.0.0)
• Considered corresponding documentation changes
• Contributed any configuration settings changes to the configuration reference
• if you added or changed Rich Configurable Fields for a Native Connector, you made a corresponding PR in Kibana

Changes Requiring Extra Attention

• Security-related changes (encryption, TLS, SSRF, etc)
• New external service dependencies added.

[cla-checker-service]

❌ Author of the following commits did not sign a Contributor Agreement:
f825188, cabe955

Please, read and sign the above mentioned agreement if you want to contribute to this project