Fix issues with adjusting min/max values for size and cmap

[Carifio24]

Currently there are two issues with adjusting values for scatter layer options, both of which this PR fixes:

• In linear (colormap) mode, the min and max values for the cmap can't be set from the widget. If the values are updated externally, the widget will update, but changing values from the widget has no effect (that is, the value in the state is not updated). The reason for this is that the deserialization line here catches cmap_vmin and cmap_vmax as well as cmap.
• The text fields used for the min/max size values in linear size mode (and those for the colormap after the above issue is fixed) update the state values to be strings rather than numbers. I think the correct fix for this (which this PR applies) is to use the glue-float-field component for handling these values.

[codecov]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (c98cb9d) 87.33% compared to head (4d611ee) 87.33%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #395   +/-   ##
=======================================
  Coverage   87.33%   87.33%           
=======================================
  Files          89       89           
  Lines        5013     5013           
=======================================
  Hits         4378     4378           
  Misses        635      635           

Files Changed	Coverage Δ
glue_jupyter/state_traitlets_helpers.py	85.57% <100.00%> (ø)

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