Update last modified time when a template or file changes in MFResourceLoaderModule

I can't believe we have been using this hacky implementation of getModifiedTime since
Idf5bde24a1e0e512fa9897190fed0b1e329f256d

Bug: 62010
Change-Id: I294e5e731e4c0ea13b73f8e1c16b88af520264a7
Merge "Update last modified time when a template or file changes in MFResourceLoaderModule"