[pgAdmin4][patch] Remove extra brackets in CREATE Script and DDL Comparison

Hi, all

Extra brackets appear in CREATE Script and DDL Comparison,
please refer to the attachment error1.png and error2.png for details.

■ scenario
The step is as follow:
1) Connect to pg9.6 or pg9.5
2) The SQL to create the trigger is as follows.
---------------------------------------------
CREATE TRIGGER tg1
    BEFORE INSERT
    ON public.tb1
    FOR EACH ROW
    WHEN (new.c1 > 0)
    EXECUTE PROCEDURE public.tf1();
---------------------------------------------

3) Right click  tg1
4) Click CREATE Script

The SQL shown in 'Query Editor' is as follows.
---------------------------------------------
CREATE TRIGGER tg1
    BEFORE INSERT
    ON public.tb1
    FOR EACH ROW
    WHEN ((new.c1 > 0))   brackets appears twice.
    EXECUTE PROCEDURE public.tf1();
------------------------------------------------

■ The detail of cause:
file: web\pgadmin\browser\server_groups\servers\databases\schemas\tables\templates\triggers\sql\pg\default\create.sql

WHEN ({{ data.whenclause }}){% endif %}

There are already brackets in data.whenclause.

■ The summary of correction
file: web\pgadmin\browser\server_groups\servers\databases\schemas\tables\templates\triggers\sql\pg\default\create.sql
- WHEN ({{ data.whenclause }}){% endif %}
+ WHEN {% if not data.oid %}({% endif %}{{ data.whenclause }}{% if not data.oid %}){% endif %}{% endif %}

Refer to the following code for the correction method.
file: web\pgadmin\browser\server_groups\servers\databases\schemas\tables\templates\triggers\sql\pg\10_plus\create.sql
WHEN {% if not data.oid %}({% endif %}{{ data.whenclause }}{% if not data.oid %}){% endif %}{% endif %}

Here is a patch for create.sql
Please review.

Best Regards!
Zhangjie