[Android] Fix USD balance in rewards panel

[deeppandya]

Description

USD balance always shows 0.0

Steps to reproduce

1. add fund to the account
2. notice that it shows 0.0 to usd balance

Actual result

USD balance is always 0.0 in rewards panel

Expected result

USD balance should show the correct value.

Issue reproduces how often

Issue happens on

• Current Play Store version?
• Beta build?

Device details

• Install type (ARM, x86):
• Device (Phone, Tablet, Phablet):
• Android version:

Brave version

Website problems only

• Does the issue resolve itself when disabling Brave Shields?
• Does the issue resolve itself when disabling Brave Rewards?
• Is the issue reproducible on the latest version of Chrome?

Additional information

[btlechowski]

Verification passed on BraveModernarm v1.10.92 on Samsung Galaxy Tab S5e (Android 9.0)

From UGP grant:

From Verified wallet + UGP grant

---

Verification passed on Samsung Galaxy J3 version 5.1.1 running BraveModernaram 1.10.92.apk

• Verified the USD value is displayed correctly in Rewards panel when wallet is funded via UGP grants
  UGP grants
  

• Verified that USD value is displayed correctly in Rewards panel when the wallet is funded via UGP grants+KYC'd uphold account
  

• Verified that the USD valu is displayed as expected in other areas like Rewards summary, AC panel, Monthly tip panel, One-time tips panel and Tipping banner.