Gemini toggle in brave://settings#newTab should not be available in unsupported regions

[ryanml]

Currently, the option to toggle the Gemini widget in brave://settings#newTab is always available. It should be present/hidden depending on whether or not Gemini is supported.

Steps to Reproduce

1. Fresh profile with an unsupported install region (Japan for instance)
2. Navigate to brave://settings#newTab.

Result

Gemini toggle option is available

Expected Result

Gemini toggle option is hidden

[GeetaSarvadnya]

Verification passed on

Brave	1.14.67 Chromium: 85.0.4183.83 (ಅಧಿಕೃತವಾಗಿ ನಿರ್ಮಿಸಿ) dev (64-ಬಿಟ್)
ಪರಿಷ್ಕರಣೆ	94abc2237ae0c9a4cb5f035431c8adfb94324633-refs/branch-heads/4183@{#1658}
OS	Windows 10 OS Version 1809 (Build 17763.1397)

• Verified the STR from the description
• OS Locale is set to India (Kannada) and verified that Gemini toggle is not shown in brave://settings#newTab
• Verified that Gemini widget isn't shown in NTP and Dashboard settings

---

Verification passed on

Brave	1.14.74 Chromium: 85.0.4183.83 (Official Build) dev (64-bit)
Revision	94abc2237ae0c9a4cb5f035431c8adfb94324633-refs/branch-heads/4183@{#1658}
OS	Linux

• Verified steps from issue description
• Verified Gemini widget is removed from NTP for unsupported region
• Verified Gemini widget is not shown in Add card dashboard settings for unsupported region
• Verified Gemini option is not shown in New Tab page settings for unsupported region

---

Verification passed on

Brave	1.14.74 Chromium: 85.0.4183.83 (Official Build) dev (64-bit)
Revision	94abc2237ae0c9a4cb5f035431c8adfb94324633-refs/branch-heads/4183@{#1658}
OS	macOS Version 10.15.5 (Build 19F101)

• Verified steps from issue description
• Verified Gemini widget is removed from NTP for unsupported region
• Verified Gemini widget is not shown in Add card dashboard settings for unsupported region
• Verified Gemini option is not shown in New Tab page settings for unsupported region