Ensure minimal number of GraphArrayView invalidation calls

[cmalinmayor]

Currently, GraphArrayView invalidates the old and new bboxes in the cache any time any node attribute is updated, including totally unrelated ones.

Also, it appears that SQLGraph emits the signal that triggers this twice:

tracksdata/src/tracksdata/graph/_sql_graph.py

Lines 2110 to 2111 in 13f9ba8

	for node_id in updated_node_ids:
	self.node_updated.emit(node_id, old_attrs_by_id[node_id], new_attrs_by_id[node_id])

and

tracksdata/src/tracksdata/graph/_sql_graph.py

Lines 2119 to 2120 in 13f9ba8

	for node_id in updated_node_ids:
	self.node_updated.emit(node_id, old_attrs_by_id[node_id], new_attrs_by_id[node_id])

Every cache invalidation is expensive, and re-invaliding the same area multiple times resets any progress already made in loading.

This PR ensures the following behavior for all graph backends:

• If the spatial bbox and attr_key are unchanged, do not invalidate the cache
• If the spatial box is unchanged but the attr_key changes, invalidate the cache once
• If the spatial bbox is changed, invalidate the cache twice (old and new bboxes)