Ads Settings should display BAT with 1 decimal place

[ryanml]

Test plan:

1. Enable Rewards
2. Navigate to brave://rewards

Expected:
Estimated pending rewards displays as 0.0 BAT

Actual:

[LaurenWags]

@ryanml @NejcZdovc I'm not finding this in 1.2.x but it is merged into master (1.3.x) per https://github.com/brave/brave-core/commits/master?after=0342c2949a9ea06ff3ea146ba0c51665549c91e1+279.

Can the milestone on this issue and the PR be adjusted to reflect 1.3.x or are you going to be requesting uplift to 1.2.x?

Marking as QA/Blocked until this is decided. cc @kjozwiak @rebron

[btlechowski]

Any updates on the concerns raised by @LaurenWags ?

[NejcZdovc]

@LaurenWags yup this was marked wrongly, changed to 1.3

[btlechowski]

Verification passed on

Brave	1.3.81 Chromium: 79.0.3945.88 (Official Build) beta (64-bit)
Revision	c2a58a36b9411c80829b4b154bfcab97e581f1f3-refs/branch-heads/3945@{#954}
OS	Ubuntu 18.04 LTS

Verified test plan from the description. Also verified other instances of BAT values and made sure they all have 1 decimal place

Verified passed with

Brave	1.3.86 Chromium: 79.0.3945.88 (Official Build) beta (64-bit)
Revision	c2a58a36b9411c80829b4b154bfcab97e581f1f3-refs/branch-heads/3945@{#954}
OS	macOS Version 10.14.6 (Build 18G103)

• Verified STR from description

Verification passed on

Brave	1.3.91 Chromium: 79.0.3945.117 (Official Build) beta (64-bit)
Revision	04f0a055010adab4484f7497fbfdbf312c307f1d-refs/branch-heads/3945@{#1019}
OS	Windows 10 OS Version 1803 (Build 17134.1006)

• Verified STR from description