Remove blanket exception catching in plot_widget

This code snip is catching all exceptions happening in the plotter code. Catching any exception is an anti-pattern, and by printing the exception to stderr sidesteps a logging systems ability to pick up any error messages.

https://github.com/equinor/ert/blob/7f03ea682594826323774a68d161021fd5054a16/src/ert/gui/tools/plot/plot_widget.py#L226-L237

Open src/ert/gui/tools/plot/plot_widget.py at lines 226-237 and inspect how exceptions from the plotter are currently caught and reported. Remove the blanket exception handling while preserving the plotter's intended error behavior and allowing errors to reach the logging system; done means broad exceptions are no longer printed directly to stderr.

Written by the indexing model from the issue text.