pgAdmin 4 commit: Prevent an error when closing the Sort/Filterdialogu

Prevent an error when closing the Sort/Filter dialogue with an empty filter string. Fixes #3970

Branch
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master

Details
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https://git.postgresql.org/gitweb?p=pgadmin4.git;a=commitdiff;h=944cc55df7c141b59dd0fa269ef963f1c89b7f08
Author: Akshay Joshi <akshay.joshi@enterprisedb.com>

Modified Files
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docs/en_US/release_notes_4_3.rst       |  1 +
web/pgadmin/tools/sqleditor/command.py | 35 ++++++++++++++++++----------------
2 files changed, 20 insertions(+), 16 deletions(-)