Assert @autofill::PersonalDataManager::IsExperimentalWalletIntegrationEnabled()

Assert @autofill::PersonalDataManager::IsExperimentalWalletIntegrationEnabled()

Any preference before being queried out needs to be set first.
In the specific case of kAutofillWalletSyncExperimentEnabled
it happens when AutofillManager::RegisterProfilePrefs is called.

However, chromium-efl is being initializing preferences on demand,
at the time "browser context" is created.
Patch adds this specific missing one.

Original beta/m42 patch:
- 165.213.202.130/gerrit/#/c/92065/ , reviewed by
Janusz Majnert, arno renevier.

Bug: http://107.108.218.239/bugzilla/show_bug.cgi?id=13114

Reviewed by: a.renevier, sns.park

Change-Id: I7af2e61bbc28fff9794206f6178d6791decbbe15
Signed-off-by: Antonio Gomes <a1.gomes@samsung.com>