Deflake Dual channel replication test batch

Deflaked the following tests:
1. dual-channel-replication with multiple replicas
2. Test diverse replica sync: dual-channel on/off
3. Test replica's buffer limit reached
4. dual-channel-replication fails when primary diskless disabled

First check that replica is online and then wait for value to propegate.

test failed in
https://github.com/valkey-io/valkey/actions/runs/9986538309/job/27599242506

Signed-off-by: naglera <[email protected]>

tests/integration/dual-channel-replication.tcl

@@ -358,12 +358,12 @@ start_server {tags {"dual-channel-replication external:skip"}} {
                 assert {[s -2 replicas_replication_buffer_size] <= 16385*2}
 
                 # Wait for sync to succeed 
-                wait_for_value_to_propegate_to_replica $primary $replica1 "key4"
                 wait_for_condition 50 1000 {
                     [status $replica1 master_link_status] == "up"
                 } else {
                     fail "Replica is not synced"
                 }
+                wait_for_value_to_propegate_to_replica $primary $replica1 "key4"
             }
 
             $replica1 replicaof no one
@@ -1107,7 +1107,5 @@ start_server {tags {"dual-channel-replication external:skip"}} {
                 fail "Replica offset didn't catch up with the primary after too long time"
             }            
         }
-
-
     }
-}
+}