software/theia: Revert libsecret path resolution

It appears no longer needed to use LD_LIBRARY_PATH to ensure the
correct runtime path resolution of libsecret in theia's `keytar`
component. Also LD_LIBRARY_PATH was leaking into theia's environment
and affecting tests launched from within theia.

This reverts commit 681ec188.

software/theia/software.cfg

@@ -358,7 +358,6 @@ template =
   inline:
   #!/bin/sh
   cd ${theia:location}
-  export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:${libsecret:location}/lib:${gettext:location}/lib:${glib:location}/lib"
   exec ${yarn:location}/bin/yarn theia start "$@"
 
 [theia-open]