Fix failing TestRealtimePresence_Sync250_RTP4 test

[lmars]

The TestRealtimePresence_Sync250_RTP4 is often failing with the following error:

=== RUN   TestRealtimePresence_Sync250_RTP4
    realtime_presence_integration_test.go:91: 
        	Error Trace:	realtime_presence_integration_test.go:91
        	Error:      	Received unexpected error:
        	            	[ErrorInfo :Rate limit exceeded; request rejected (nonfatal); metric = channel.maxRate; interval = 2024-12-02:19:53:6; permitted rate = 250; current rate = 300 code=42910 rate limit exceeded (nonfatal): request rejected (unspecified) statusCode=429] See https://help.ably.io/error/42910
        	Test:       	TestRealtimePresence_Sync250_RTP4
        	Messages:   	rg.Wait()=[ErrorInfo :Rate limit exceeded; request rejected (nonfatal); metric = channel.maxRate; interval = 2024-12-02:19:53:6; permitted rate = 250; current rate = 300 code=42910 rate limit exceeded (nonfatal): request rejected (unspecified) statusCode=429] See https://help.ably.io/error/42910

For example, see this build failure:

https://github.com/ably/ably-go/actions/runs/12126601920/job/33809045541

We should investigate and fix this.

┆Issue is synchronized with this Jira Task by Unito