build: Move Meson dependency() calls to where they’re used

This avoids making the project depend on all its dependencies, some of
which are optional, when being built as a Meson subproject.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

src/sysprof/meson.build

@@ -17,7 +17,7 @@ sysprof_deps = [
   libsysprof_capture_dep,
   libsysprof_dep,
   libsysprof_ui_dep,
-  pangoft2_dep,
+  dependency('pangoft2', required: false),
 ]
 
 sysprof = executable('sysprof', sysprof_resources + sysprof_sources,