Handle nComponent in process_inverse (#743)

Handle reduced size files computed with wavelet-MEM.
This was implemented on `process_inverse_2028` in #733

toolbox/process/functions/process_inverse.m

@@ -694,7 +694,10 @@
                 OPTIONS.NoiseCovRaw   = NoiseCov;
                 % Call the mem solver
                 [Results, OPTIONS] = be_main(HeadModel, OPTIONS);
-                Results.nComponents = round(max(size(Results.ImageGridAmp,1),size(Results.ImagingKernel,1)) / nSources);
+                if ~isfield(Results, 'nComponents') || isempty(Results.nComponents)
+                    Results.nComponents = round(max(size(Results.ImageGridAmp,1),size(Results.ImagingKernel,1)) / nSources);
+                end
+
                 % Get outputs
                 DataFile = OPTIONS.DataFile; 
                 Time     = OPTIONS.DataTime;