pgAdmin 4 commit: Ensure the File Manager honours the file type while t

Ensure the File Manager honours the file type while traversing the directories. Fixes #1858

When a File Manager is closed by clicking cancel button. Its dom element not destroyed.. So on traversing into
directories,when it tries to get currently selected file type, it looks into the dom element but it gets dom of
previousdialogs not of currently dialog. 

Now whenever an instance of File Manager is closed. its dom elements are also destroyed.

Branch
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master

Details
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http://git.postgresql.org/gitweb?p=pgadmin4.git;a=commitdiff;h=1e66119ef58e4d310daaece697e3546ec1380712
Author: Surinder Kumar <surinder.kumar@enterprisedb.com>

Modified Files
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.../templates/file_manager/js/file_manager.js      | 28 +++++++++++++++++-----
.../sqleditor/templates/sqleditor/js/sqleditor.js  |  7 ++++++
2 files changed, 29 insertions(+), 6 deletions(-)