pgAdmin 4 commit: Ensure that dashboard graph API is not called after t

Ensure that dashboard graph API is not called after the panel has been closed. Fixes #7518

Branch
------
master

Details
-------
https://git.postgresql.org/gitweb?p=pgadmin4.git;a=commitdiff;h=e59471d87da84b1f8bbf85e7efc7f25591238f94
Author: Pradip Parkale <pradip.parkale@enterprisedb.com>

Modified Files
--------------
docs/en_US/release_notes_6_12.rst             | 1 +
web/pgadmin/browser/static/js/panel.js        | 9 +++++++++
web/pgadmin/browser/static/js/panel_view.jsx  | 4 +++-
web/pgadmin/dashboard/static/js/Dashboard.jsx | 3 ++-
web/pgadmin/dashboard/static/js/Graphs.jsx    | 3 +++
5 files changed, 18 insertions(+), 2 deletions(-)