Remove "Add funds" buttons in Rewards (remove add_url and withdraw_url from ExternalWallet)

[Miyayes]

Description

The "Add funds" button does not serve its purpose very well in Rewards 2.0. We can remove it for now, and be able to clean up the code in quite a few places if it is removed. Can be re-introduced in Rewards 3.0.

@szilardszaloki Has most context.

[emerick]

@Miyayes Are we dropping the entire "Not enough tokens. Please add funds." section from the tip banner? Or just removing the "Please add funds" portion?

[Miyayes]

@emerick Hm, that's a good point. I think it would make sense to just drop "Please add funds" part, and keep the "Not enough tokens" part?

[emerick]

@Miyayes One more question: does this mean removing the "Add funds" notification? For the moment, I've renamed it to an "Insufficient funds" notification, but let me know if you'd like to remove or adjust it.

[emerick]

Just noting here that we decided to remove the "insufficient funds" notifications as they are confusing to users and don't provide much value.

[LaurenWags]

Verified with

Brave | 1.48.129 Chromium: 109.0.5414.87 (Official Build) beta (x86_64)
-- | --
Revision | 2dc18eb511c56e012081b4abc9e38c81c885f7d4-refs/branch-heads/5414@{#1241}
OS | macOS Version 12.6.2 (Build 21G320)

Uphold - PASSED

Prior to fix in 1.47.171:

brave://rewards	Rewards Panel	Tip Banner

After the fix with 1.48.129:
Confirmed "Add funds" removed from wallet panel on brave://rewards, panel from BAT logo, and tip banner (when applicable).

brave://rewards	Rewards Panel	Tip Banner

Gemini - PASSED

Prior to fix in 1.47.171:

brave://rewards	Rewards Panel

After the fix with 1.48.129:
Confirmed "Add funds" removed from wallet panel on brave://rewards and panel from BAT logo. Unable to check tip banner due to balance being too high (max tip amount is 100 BAT, unable to get Gemini balance under 100 BAT)

brave://rewards	Rewards Panel

bitFlyer - PASSED

Prior to fix in 1.47.171:

brave://rewards	Rewards Panel	Tip Banner

After the fix with 1.48.129:
Confirmed "Add funds" removed from wallet panel on brave://rewards, panel from BAT logo, and tip banner (when applicable).

brave://rewards	Rewards Panel	Tip Banner

Note - Unable to confirm the "Insufficient Funds" notification was removed (test plan from #3286 did not display the notification on 1.47.x, other tests proved unsuccessful as well). After conferring with Emerick, decided that since notification was removed it was ok to skip confirming this.

[stephendonner]

Verified PASSED using Brave 1.48.149, Chromium 109.0.5414.119 on a Google Pixel XL (arm64) running Android 9

Uphold - PASSED

Confirmed + Add Funds was removed from:

• brave://rewards
• Rewards panel
• setting a custom-tip value more than the available BAT automatically reduces it to 100 (in my case), without the same error message as desktop

brave://rewards	Rewards panel	tip

Gemini - PASSED

Confirmed + Add Funds was removed from:

• brave://rewards
• Rewards panel
• setting a custom-tip value more than the available BAT automatically reduces it to 100 (in my case), without the same error message as desktop

brave://rewards	Rewards panel	tip

bitFlyer - PASSED

Confirmed + Add Funds was removed from:

• brave://rewards
• Rewards panel
• setting a custom-tip value more than the available BAT automatically reduces it to 100 (in my case), without the same error message as desktop

brave://rewards	Rewards panel	tip