Fix to handle the error in `FindDeploymentStatusByID`

[noahingh]

Describe the bug
The server is crashing in the process of forwarding the deployment event.

Logs or Screenshots

Logs

gitploy-5cb78f8c9c-8g8t4 gitploy panic: runtime error: invalid memory address or nil pointer dereference
gitploy-5cb78f8c9c-8g8t4 gitploy [signal SIGSEGV: segmentation violation code=0x1 addr=0x90 pc=0xdd3cec]
gitploy-5cb78f8c9c-8g8t4 gitploy
gitploy-5cb78f8c9c-8g8t4 gitploy goroutine 492 [running]:
gitploy-5cb78f8c9c-8g8t4 gitploy github.com/gitploy-io/gitploy/internal/server/api/v1/stream.(*Stream).GetEvents.func1(0xc000396a00)
gitploy-5cb78f8c9c-8g8t4 gitploy 	/server/internal/server/api/v1/stream/events.go:42 +0x70c
gitploy-5cb78f8c9c-8g8t4 gitploy reflect.Value.call({0x1135da0, 0xc00018b950, 0x13}, {0x1330b06, 0x4}, {0xc00024c960, 0x1, 0x1})
gitploy-5cb78f8c9c-8g8t4 gitploy 	/usr/local/go/src/reflect/value.go:556 +0x845
gitploy-5cb78f8c9c-8g8t4 gitploy reflect.Value.Call({0x1135da0, 0xc00018b950, 0xc000545100}, {0xc00024c960, 0x1, 0x1})
gitploy-5cb78f8c9c-8g8t4 gitploy 	/usr/local/go/src/reflect/value.go:339 +0xc5
gitploy-5cb78f8c9c-8g8t4 gitploy github.com/asaskevich/EventBus.(*EventBus).doPublish(0xc000107dc8, 0xc00018b980, {0x50d125, 0xc00047b800}, {0xc000545100, 0xc0000b27e0, 0x0})
gitploy-5cb78f8c9c-8g8t4 gitploy 	/go/pkg/mod/github.com/asaskevich/!event!bus@v0.0.0-20200907212545-49d423059eef/event_bus.go:160 +0x53
gitploy-5cb78f8c9c-8g8t4 gitploy github.com/asaskevich/EventBus.(*EventBus).doPublishAsync(0xc000058701, 0x448605, {0x133a78f, 0xa8c54e}, {0xc000545100, 0x15021f8, 0xc00018a870})
gitploy-5cb78f8c9c-8g8t4 gitploy 	/go/pkg/mod/github.com/asaskevich/!event!bus@v0.0.0-20200907212545-49d423059eef/event_bus.go:168 +0xa5
gitploy-5cb78f8c9c-8g8t4 gitploy created by github.com/asaskevich/EventBus.(*EventBus).Publish
gitploy-5cb78f8c9c-8g8t4 gitploy 	/go/pkg/mod/github.com/asaskevich/!event!bus@v0.0.0-20200907212545-49d423059eef/event_bus.go:152 +0x5a5

Additional context
I think the FindDeploymentStatusByID doesn't return an error even though it gets an error from the database.