Cleanup iOS Search Engines

[jhreis]

Match:
brave/brave-browser#3316

iOS Search Repo:
https://github.com/brave/Brave-iOS-SearchPlugins

Search engines to support:

• Google
• DDG
• Qwant
• StartPage
• Bing (excluded from tr, ru, th)
• Yandex (included in tr, ru, kk, be)
• Any pre-set search engines

on iOS there is a search engine for "normal" browsing and one for "Private", so maybe up to 2 additional search engines.

• Infogalactic will be completely dropped regardless of user's set engine in either mode.

[kjozwiak]

Waiting for #920 to be resolved before verifying.

[LaurenWags]

Using iPad 5th Gen and 1.8 (19.2.26.22) on Test Flight:

• Verified test cases 1, 2, 3 from Cleans up pre-populated search engines. brave-core#1648 for US, France, Germany for both Normal and Private tab search engines. (Additional testing notes can be found at Default search engines that were removed are being reverted to region defaults #920 (comment))
• Verified Bing customizations for the following regions: Turkey (language=Turkish), Russia (language=Russian), Thailand (language=Thai). Note, for Thailand Google was default search engine. Other two had Yandex as default.
• Verified Yandex customizations for the following regions: Turkey (language=Turkish), Russia (language=Russian), Kazakhstan (language=Russian), and Belarus (language=Russian). Note, for these countries Yandex was the default search engine not Google.
  Note - Bing/Yandex customizations use language, but Qwant customization uses region.
• Verified if Infogalactic was set as search engine for Normal or Private tab, when updated to 1.8 it was replaced with the region's default search engine. Verified for US, France, and Germany regions.

Verified using iPhone SE, Brave 1.8 (19.2.26.22) on Test Flight.

[kjozwiak]

Went through the above cases that @LaurenWags outlined using the following devices:

• iPad Mini 4 running iOS 12.1.4
• iPhone 6s+ running iOS 12.1.4