add backend tests

[mlapaglia]

No description provided.

[github-actions]

Package	Line Rate	Branch Rate	Health
_services	20%	0%	➖
plates	22%	0%	➖
plates.edit-plate	100%	100%	✔
plates.plate	42%	17%	➖
settings	19%	100%	➖
settings.alerts	36%	0%	➖
settings.alerts.pushover	31%	0%	➖
settings.alerts.webpush	33%	0%	➖
settings.cameras	35%	40%	➖
settings.cameras.camera	56%	100%	➖
settings.cameras.edit-camera	41%	100%	➖
settings.cameras.edit-camera.camera-mask	14%	0%	➖
settings.enrichers	28%	0%	➖
settings.forwards	39%	0%	➖
settings.ignores	39%	0%	➖
settings.openalpr-agent	45%	12%	➖
settings.system-logs	58%	100%	➖
signalr	17%	100%	➖
snackbar	67%	30%	➖
Summary	29% (260 / 909)	6% (9 / 143)	➖

Minimum allowed line rate is 0%

[github-actions]

Package	Line Rate	Branch Rate	Health
OpenAlprWebhookProcessor.Server	0%	1%	➖
Summary	0% (81 / 22071)	1% (6 / 728)	➖

Minimum allowed line rate is 0%