Fixes the "There is a more recent autosave of your changes" notice from not
being removed when the dismiss button is clicked.
The problem is caused by the notice being initialized twice: once by the
`common` script and then again by the `customize-controls` script.
This temporary fix prevents `customize-controls` from initializing a notice if
it has already been initialized.
A better fix would be to not initialize notices twice. This can be done by
removing `common` as a dependency of `updates` when `deprecateL10nObject` is
removed.
When this happens (est: 5.7), this temporary fix should be reverted.
Fixes#51425.
See #51317.
Props karthikbhatb, dlh, SergeyBiryukov.
Built from https://develop.svn.wordpress.org/trunk@49625
git-svn-id: http://core.svn.wordpress.org/trunk@49363 1a063a9b-81f0-0310-95a4-ce76da25c4cd
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