monitor: restore previous state when hitting escape while editing the filter regex
monitor: restore previous state when hitting escape while editing the filter regex

IMO this is more intuitive than disabling filtering.

Signed-off-by: Andreas Lauser <429495c8e182c230dc2e2e45b7683abab22a535c@mbition.io>
Signed-off-by: Oliver Kopp <145f9cd3bd4b8f6f87f6a0c88db241a6cbaa88bd@mbition.io>

cantools/cantools,eerimoq/cantools