do not provide monthly statements for data prior to 1.3.x

[LaurenWags]

Description

Since Rewards has undergone many refactors and database migrations, it may make sense to not provide monthly statements for data that existed prior to 1.3.x (approx early Feb timeframe on Release channel).

cc @mandar-brave @NejcZdovc @jenn-rhim for additional comments

Steps to Reproduce

1. View monthly statements

Actual result:

data prior to VG/1.3.x may be missing/incomplete

Expected result:

do not show ability to view statements for data added prior to 1.3.x

Reproduces how often:

easily if you have had a profile for several months

Brave version (brave://version info)

1.7.x

Version/Channel Information:

• Can you reproduce this issue with the current release? n/a
• Can you reproduce this issue with the beta channel? yes
• Can you reproduce this issue with the dev channel? yes
• Can you reproduce this issue with the nightly channel? yes

Other Additional Information:

• 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?

Miscellaneous Information:

cc @NejcZdovc @mandar-brave @jenn-rhim @brave/legacy_qa @rebron

[LaurenWags]

Verified passed with

Brave	1.7.98 Chromium: 81.0.4044.113 (Official Build) (64-bit)
Revision	e3225dafb0475864a1812a374d73a92e391635ac-refs/branch-heads/4044@{#936}
OS	macOS Version 10.14.6 (Build 18G3020)

• Confirmed with 1.7.92 I could see data prior to Feb 2020:

• Updated to 1.7.98 and confirmed could only see data from Feb 2020 onwards per Removes monthly report for versions before 1.3 brave-core#5216

Verification passed on

Brave	1.7.98 Chromium: 81.0.4044.113 (Official Build) (64-bit)
Revision	e3225dafb0475864a1812a374d73a92e391635ac-refs/branch-heads/4044@{#936}
OS	Ubuntu 18.04 LTS

• Confirmed with 1.7.92 I could see data prior to Feb 2020:
  

• Updated to 1.7.98 and confirmed could only see data from Feb 2020 onwards per Removes monthly report for versions before 1.3 brave-core#5216
  

Verification passed on

Brave	1.7.98 Chromium: 81.0.4044.113 (Official Build) (64-bit)
Revision	e3225dafb0475864a1812a374d73a92e391635ac-refs/branch-heads/4044@{#936}
OS	Windows 10 OS Version 1803 (Build 17134.1006)

• Confirmed with 1.7.92 I could see data prior to Feb 2020:
  

• Updated to 1.7.98 and confirmed could only see data from Feb 2020 onwards per Removes monthly report for versions before 1.3 brave-core#5216