Update of BaseModel.php to fix INSERT issue

[katie1348]

Applied the fix that enables the INSERT to work correctly when inserting a row that already contains data.

Each pull request should address a single issue and have a meaningful title.

Description
Applied the fix suggested by @arbitmcdonald in Bug: onlyChanged is currently true for INSERT #4247

Checklist:

[x] Securely signed commits
[x] Component(s) with PHPdocs
[x] Unit testing, with >80% coverage
[x] User guide updated
[x] Conforms to style guide

[paulbalandan]

We would need tests to verify that the fix is actually working.

[paulbalandan]

You can take at a look at tests/system/Models/ dir to check the tests for the Model.

[katie1348]

OK, so it looks like the error is a coding standards error of == rather than ===.

Does his mean I need to start the process from the beginning to make this change?

[paulbalandan]

No need to open new PR. You can do the edit directly here.

[paulbalandan]

Replaced by #4980