Merge branch '505527-move-vul-file-content-viewer-to-shared' into 'master'

Move 'vulnerability_file_content_viewer' to shared folder

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/174350



Merged-by: Andrew Fontaine <afontaine@gitlab.com>
Approved-by: Eduardo Bonet <ebonet@gitlab.com>
Approved-by: Andrew Fontaine <afontaine@gitlab.com>
Co-authored-by: Chen Charnolevsky <ccharnolevsky@gitlab.com>