pgAdmin 4 commit: 1) Ensure that sequence should be created withPrivil

1) Ensure that sequence should be created with Privileges.
2) Updated the validation for blank values in Definition tab.

Branch
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master

Details
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https://git.postgresql.org/gitweb?p=pgadmin4.git;a=commitdiff;h=a0010aac318cb65303680fa2d86212a898794641

Modified Files
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.../servers/databases/schemas/sequences/__init__.py          |  2 +-
.../databases/schemas/sequences/static/js/sequence.js        |  3 +++
.../sequences/templates/sequence/sql/default/create.sql      | 12 ++++++------
3 files changed, 10 insertions(+), 7 deletions(-)