pgAdmin 4 commit: Added missing imports and remove unused imports from

Added missing imports and remove unused imports from schema diff.

Branch
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master

Details
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https://git.postgresql.org/gitweb?p=pgadmin4.git;a=commitdiff;h=641701ca16f5e00f2b3cc129bdcbe4601f959865

Modified Files
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.../servers/databases/schemas/tables/schema_diff_utils.py  |  2 +-
web/pgadmin/tools/schema_diff/__init__.py                  |  3 ++-
web/pgadmin/tools/schema_diff/compare.py                   |  5 ++---
web/pgadmin/tools/schema_diff/directory_compare.py         | 14 +++++++++-----
4 files changed, 14 insertions(+), 10 deletions(-)