No, libqtm-11-declarative installs Qt Mobility 1.1 into /opt - it doesn't replace any files. You can remove the FM4 App and that package using:

It will show you which packages are going to be removed - if there are packages that you use (and don't want to remove), just remove "fm4app" - in this case, one of your other packages depend on libqtm-11-declarative and you don't want to remove it. It could also be that installing libqtm-11-declarative installed some other Qt Mobility 1.1 packages as a dependency, you can check this with:

If there are packages listed (with "ii" at the beginning - ignore "rc" ones; these are already removed except for the configuration files), you can remove them too - but again, it doesn't cause any "damage" or irreversible changes to your system, the only 'disadvantage' that you have is that these packages take up a little space on your /opt partition.