[ads] Preserve search ad info bar preference when clearing ads data

[aseren]

Resolves brave/brave-browser#45213

Test plan

Test case 1

• Fresh install
• Open search.brave.software in a new tab
• Make Giraffe search query
• Click the search result ad
  EXPECTATION: Search result ad infobar was shown
• Open search.brave.software in a new tab
• Make Giraffe search query
• Click the search result ad
  EXPECTATION: Search result ad infobar was NOT shown

Test case 2

• Install Brave version 1.79.x (an old version)
• Open search.brave.software in a new tab
• Make Giraffe search query
• Click the search result ad
  EXPECTATION: Search result ad infobar was shown
• Update the browser to version 1.80.x
• Open search.brave.software in a new tab
• Make Giraffe search query
• Click the search result ad
  EXPECTATION: Search result ad infobar was NOT shown

Test case 3

• Install Brave version 1.79.x (an old version)
• Update the browser to version 1.80.x
• Open search.brave.software in a new tab
• Make Giraffe search query
• Click the search result ad
  EXPECTATION: Search result ad infobar was shown

[tmancey]

Wrong date.

[aseren]

Fixed

[brave-builds]

Warning

You have got a presubmit warning. Please address it if possible.

Discovered possible removal of preference registrations.

Please make sure to properly deprecate preferences by clearing their
value for a couple of milestones before finally removing the code.
Otherwise data may stay in the preferences files forever. See
Migrate*Prefs() in chrome/browser/prefs/browser_prefs.cc and
chrome/browser/prefs/README.md for examples.
This may be a false positive warning (e.g. if you move preference
registrations to a different place).

Items:

components/brave_ads/core/internal/prefs/obsolete_pref_util.cc: -  registry->RegisterBooleanPref(kHasMigratedConversionState, false);
components/brave_ads/core/internal/prefs/obsolete_pref_util.cc: -  registry->RegisterBooleanPref(kHasMigratedNotificationState, false);
components/brave_ads/core/internal/prefs/obsolete_pref_util.cc: -  registry->RegisterBooleanPref(kHasMigratedRewardsState, false);
components/brave_ads/core/internal/prefs/obsolete_pref_util.cc: -  registry->RegisterBooleanPref(kShouldMigrateVerifiedRewardsUser, false);

[brave-builds]

Released in v1.80.59