New Template Files

[Claudio-Merola]

Overview/Summary

Improve the file path validation methods
Add the new excel template files for Expert-Analysis and Assessment-Findings-Report

As part of this pull request I have

• Read the Contribution Guide and ensured this PR is compliant with the guide
• Checked for duplicate Pull Requests
• Associated it with relevant GitHub Issues or ADO Work Items (Internal Only)
• Ensured my code/branch is up-to-date with the latest changes in the main branch
• Ensured PR tests are passing
• Performed testing and provided evidence (e.g. screenshot of output) for any changes associated to ARG queries
• Updated relevant and associated documentation (e.g. Contribution Guide, Docs etc.)