[Android] Advanced server selection follow up

[deeppandya]

Description

Based on the suggestions from guardian team and as a follow up to #36277, we need to update existing changes to include country and continent variables in the Region.
We also need to update the logic around the way we persist and identify selected region after an upgrade.

Test Plan :

Please follow the test plan mentioned in the main PR : brave/brave-core#25089

[srirambv]

Marking as QA/Blocked as #41477 is known issue which is waiting on #25604 to be uplifted

[kjozwiak]

The above requires 1.71.112 or higher for 1.71.x verification 👍 The above can be verified alongside #36277 once we start running through the VPN feature via 1.71.x.

[hffvld]

Verified on Pixel 7 using version(s):

Device/OS: Pixel 7 / panther_beta-user 15 AP41.240823.009 release-keys
Brave build: 1.71.112
Chromium: 130.0.6723.44 (Official Build) (64-bit) 

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"Automatic" server location

STEPS:

1. Buy an IAP subscription on a fresh profile
2. Create a VPN profile
3. Turn on VPN
4. Go to the Server selection page
5. Verify that Automatic must be selected

ACTUAL RESULTS:

• Verified that Automatic location is selected by default when enabling VPN

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1	2	3

"Optimal" server location from the selected region

STEPS:

1. Go to Server selection page
2. Disable Automatic toggle switch > Verify that your region (USA in my case) is selected by default
3. Select the USA as a region
4. On the next page, select Optimal
5. Verify that the Best server location would be selected and it could give a different location based on the available resources on the location at the time

ACTUAL RESULTS:

• Verified that your region (USA in my case) is selected by default after disabling the Automatic toggle switch.
• Verified that the Best server location must be selected when tapping on Optimal, and it could give a different location based on the available resources at the time.

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1	2	3

"Specific" server selection

STEPS:

1. Go to Server selection page
2. Select the USA as a region
3. On the next page, select Atlanta
4. Verify that Atlanta must be selected as server location

ACTUAL RESULTS:

• Verified that a specific city/server must be selected as server location when tapping the city name.

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1	2	3	4

"Upgrade" scenario

STEPS:

1. Install and launch Brave 1.70.123 > Purchase/enable VPN > Verify VPN server selection screen UI
2. Upgrade Brave to 1.71.112 > Enable VPN > Go to the Server selection page
3. Verify that the Selected region from the previous version must be selected in the new UI
4. Tap on the region
5. Verify that Optimal must be selected as we didn't have a granular details from the previous version. A new version of the app would follow the new changes moving forward.

ACTUAL RESULTS:

• Verified that Automatic is NOT selected after Brave upgrade.
• Verified that the previously selected region is still selected after Brave upgrade.
• Verified that the Optimal server location is selected by default after Brave upgrade as we didn't have granular details from the previous version. A new version of the app would follow the new changes moving forward.
• Verified that multiple radio buttons can't be selected at the same time

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Before upgrade	After upgrade