Wire SaveRecurringTip through ledger

[NejcZdovc]

Test Cases

• Ensure the case outlined under rewire SaveRecurringTip through ledger brave-core#2962 works without issues

Original Issue

We need to wire all UI triggered functions through ledger code. What SaveRecurringTip we save it directly into db.

Take example of GetRecurringTipsUI on how it should be done.

[GeetaSarvadnya]

Verification passed on

Brave	0.69.128 Chromium: 77.0.3865.75 (Official Build) (64-bit)
Revision	201e747d032611c5f2785cae06e894cf85be7f8a-refs/branch-heads/3865@{#776}
OS	Windows 10 OS Version 1803 (Build 17134.1006)

• Verified the test plan from rewire SaveRecurringTip through ledger brave-core#2962
  

• After changing the recurring tip value from BR panel, the updated recurring monthly value reflected in DB under recurring donation table
  

Set 1 BAT

Changed to 5 BAT in Panel

Changed to 0 Bat in Panel

Verified the updated recurring monthly value in DB

Verified passed with

Brave	0.69.129 Chromium: 77.0.3865.90 (Official Build) (64-bit)
Revision	58c425ba843df2918d9d4b409331972646c393dd-refs/branch-heads/3865@{#830}
OS	macOS Version 10.13.6 (Build 17G5019)

• Verified the test plan from rewire SaveRecurringTip through ledger brave-core#2962

Set initial recurring tip, it is reflected on brave://rewards:

Updated recurring tip from panel:

Update is reflected on brave://rewards: