pgAdmin 4 commit: Fixed validation errors in view/materialized view jav

Fixed validation errors in view/materialized view javascript to
determine the number columns chagned. It was trying to execute
'replace' and 'includes' function on undefined values instead of
string value.

Also - changed the warning message, and separated the 'Do you want to
continue?' syntax in separate line for better user experience.

Fixes #5053

Branch
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master

Details
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https://git.postgresql.org/gitweb?p=pgadmin4.git;a=commitdiff;h=858294f36e81fddf5da2f1538129cc2030b7d724

Modified Files
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.../databases/schemas/views/static/js/mview.js     |  5 ++-
.../databases/schemas/views/static/js/view.js      | 51 ++++++++++++++--------
2 files changed, 38 insertions(+), 18 deletions(-)