fix Restart-AzSignalR,Update-AzSignalR help files error

Author: Y-Sindo

src/SignalR/SignalR/help/Restart-AzSignalR.md

@@ -148,7 +148,7 @@ Aliases:
 Required: True
 Position: Named
 Default value: None
-Accept pipeline input: True (ByValue)
+Accept pipeline input: True (ByPropertyName)
 Accept wildcard characters: False
 ```
 

src/SignalR/SignalR/help/Update-AzSignalR.md

@@ -166,7 +166,7 @@ Aliases:
 Required: True
 Position: Named
 Default value: None
-Accept pipeline input: True (ByValue)
+Accept pipeline input: True (ByPropertyName)
 Accept wildcard characters: False
 ```