No longer auto-set the Footprint field when setting the FPID

This avoids forcing the field to the footprint name in the
library editor, which gets in the way. This doesn't specifically
inhibit the use of the field, and doesn't interfere with fields
users may have set manually (it can be cleared manually if
wished).

Removing the footprint field entirely either from all footprints
or from footprints in fpedit is quite a bit more invasive to
existing designs.

(cherry picked from commit 44b0ef64e8)

Cherry-picking forward to master to at least keep things consistent
for the time being.

Relates-To: https://gitlab.com/kicad/code/kicad/-/issues/17998

pcbnew/footprint.h

@@ -234,7 +234,6 @@ public:
     void          SetFPID( const LIB_ID& aFPID )
     {
         m_fpid = aFPID;
-        Footprint().SetText( aFPID.Format() );
     }
 
     wxString GetFPIDAsString() const { return m_fpid.Format(); }