missing value heatmap should use the raw data rather than a filtered version of data

[hsiaoyi0504]

https://github.com/MonashProteomics/Fragpipe-Analyst/blob/b6445a9f43b583be27c0ae2827c4a07b1f2ff9c6/server.R#L669

[hsiaoyi0504]

However, data without filtering results in worse performance in terms of speed.

[hsiaoyi0504]

Probably a bottom line with be adding some text description in the interface or the plot to indicate how many features are plotted.

[hsiaoyi0504]

Added in 6306c805d5d406a920aa1d2d60049.