CheckObjectsExist doesn't accept revision:path pattern

This issue was created based on the discussion in #5081 (comment 1381490348)

In the GitLab project, we would like to have a fast way of checking whether a file or files exist in a revision however, the current API gives an error:

p = Project.first
p.repository.check_objects_exist("main:README.md")

Error:

ArgumentError: 3:invalid revision: revision can't contain ':'. debug_error_string:{"created":"@1683538175.466833223","description":"Error received from peer unix:dev/gitlab-development-kit/praefect.socket","file":"src/core/lib/surface/call.cc","file_line":1063,"grpc_message":"invalid revision: revision can't contain ':'","grpc_status":3}