fix: allow disabling projections for specific instances (#10421)

# Which Problems Are Solved

The current handling of event subscriptions for actions is bad, esp. on
instances with a lot of events
(https://github.com/zitadel/zitadel/issues/9832#issuecomment-2866236414).
This led to severe problems on zitadel.cloud for such instances.

# How the Problems Are Solved

As a workaround until the handling can be improved, we introduce an
option for projections to be disabled completely for specific instances:
`SkipInstanceIDs`

# Additional Changes

None

# Additional Context

- relates to https://github.com/zitadel/zitadel/issues/9832

internal/query/projection/config.go

@@ -26,4 +26,5 @@ type CustomConfig struct {
 	ConcurrentInstances *uint
 	BulkLimit           *uint16
 	TransactionDuration *time.Duration
+	SkipInstanceIDs     []string
 }