Modified tags fail in the branch selector

When a tag has modifications (either through actual commits to the tag folder or through migrations of folders above it (e.g., the repository is moved and Follow Base Moves is enabled, or the project is renamed, etc), the Branch selector will attempt to jump from:

repo/trunk/path/to/file.txt

to

repo/tags/theTag/path/to/file.txt/path/to/file.txt

This is because we are incorrectly identifying the full path as a tagRoot in BranchSelectorUtil.getPhysicalPathAtTag, then appending the logicalTail to it.