Resolve "Too-eager urlencoding for find files links"

What does this MR do?

This MR replaces the use of encoudeURIComponent with escapeFileUrl to properly escape file paths.

Screenshots

Before	After (on 2019-12-16 6a34da1c)
20191216_fix_file_finder_escape_before	20191216_fix_file_finder_escape_after

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• [ ] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

References:

• Related to #31662 (closed)
• Blocked by !21865 (merged)