[pgAdmin4][Patch]: RM1595 - "no results to fetch error" displayed if modify definition with other table

Hi

*Issues fixed:*

1) Creating a m-view with *definition* and then updating view with* new
definition,* it results into an error *"No results to fetch"*.

2) When definition of m-view is updated, it creates a new m-view with
different OID, but it wasn't updating the old OID with new OID of tree node
in tree view. thus on switching to another tab (e.g.: sql), it throws
message *"Cannot find materialized view"*.

Please find attached patch and review.

Thanks,
Surinder Kumar