Don't change MSSQL query if no limit or offset is set

### Issue
Currently, MSSQL creates an error for each database query where no limit is set. Like for inserts, updates and the like.
See #3602 and #4869 for the issue reports.

### Solution
Add a check to the sqlsrv query class in the `processLimit()` method. Similar to what we already do in MySQL and PostgreSQL.

### Testing
@sovainfo can you explain how to reproduce the issue? As far as I understood one sees that on first page after updating?
In other places we have the code to apply the limit within the if clause.
I went the other way around and bail out if the checks are not successful. I prefer this way in this case because the actual code has another if clause and is quite a few lines long.
I think it's easier to read this way.
Also PostgreSQL has yet another way
````
		if ($limit > 0)
		{
			$query .= ' LIMIT ' . $limit;
		}

		if ($offset > 0)
		{
			$query .= ' OFFSET ' . $offset;
		}
````
So there is not really a standard anyway :smile: