Avoid unnecessary Html.fromHtml()

Check if string contains html tag, before call Html.fromHtml()

Fix: 308681068
Test: atest SubscriptionsPreferenceControllerTest
Test: atest ProviderModelSliceHelperTest NetworkProviderWorkerTest
Test: manual - on Internet page
Change-Id: Id914689f2861a8c997d18afd03ecfdf47b91c631