Cellular data fails to reconnect

From https://github.com/ubports/ubuntu-touch/issues/1954

It appears that in some random situation, toggling on cellular have no effect, no internet available. Cell indicator have an empty triangle, whereas the provider information states we are connected to "L" network:

A reboot or systemctl restart fix that situation.

Reported on devices H9+ (Pixel3a , OP5T, FP4 at least)

Might be related: https://github.com/ubports/ubuntu-touch/issues/1657