fix(network): read the hide_threshold_bytes the plugin documents - #3726

The bug

hide_threshold_bytes is offered to users under [network] in two places:

conf/glances.conf

# Set hide_zero to True to automatically hide interface with no traffic
hide_zero=False
# Set hide_threshold_bytes to an integer value to automatically hide
# interface with traffic less or equal than this value
#hide_threshold_bytes=0

docs/aoa/network.rst

[network]
hide_zero=True
hide_threshold_bytes=0

NetworkPlugin.__init__() never read it. diskio has read it since the option was introduced; network was left out:

# glances/plugins/diskio/__init__.py
self.hide_zero = config.get_bool_value(self.plugin_name, 'hide_zero', default=False)
self.hide_threshold_bytes = config.get_int_value(self.plugin_name, 'hide_threshold_bytes', default=0)

# glances/plugins/network/__init__.py
self.hide_zero = config.get_bool_value(self.plugin_name, 'hide_zero', default=False)

So the attribute stayed at the base-class default of 0 whatever the user wrote. Nothing reports it: hide_zero keeps working, it simply never applies the threshold, and an interface carrying a trickle of background traffic is shown when the user asked for it to be hidden.

The change

Read it beside hide_zero, exactly as diskio does. Two lines, no new behaviour of its own.

Tests

tests/test_network_hide_threshold.py, 5 tests. The wiring assertion alone would be weak, so the boundary is also read back out of the views dict: with hide_threshold_bytes=1024, an interface at 524 B/s stays hidden and one at 2048 B/s is revealed. The last test pins that the unconfigured default of 0 still reveals that same 524 B/s trickle, so this does not quietly change anyone's current behaviour.

Mutation — delete the added get_int_value line: 2 fail, the wiring test and the "below the threshold stays hidden" behavioural test.

tests/test_plugin_network.py and tests/test_lazy_views.py — 45 passed. ruff check and ruff format --check clean.

Independent of #3725, which fixes the comparison this threshold is used in; either can go first.