Do not include failed contributions in monthly statement

[NejcZdovc]

Description

Steps to Reproduce

1. enable rewards
2. claim grant
3. do AC
4. go to DB, go to contribution_info table and change step from -1 to -3

Actual result:

Contribution is shown in the monthly statement

Expected result:

Contribution should not be shown in monthly statement

Reproduces how often:

Brave version (brave://version info)

Version/Channel Information:

• Can you reproduce this issue with the current release?
• Can you reproduce this issue with the beta channel?
• Can you reproduce this issue with the dev channel?
• Can you reproduce this issue with the nightly channel?

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:

[LaurenWags]

Verified passed with

Brave	1.7.79 Chromium: 80.0.3987.149 (Official Build) dev (64-bit)
Revision	5f4eb224680e5d7dca88504586e9fd951840cac6-refs/branch-heads/3987_137@{#16}
OS	macOS Version 10.14.6 (Build 18G3020)

• Verified test plan from Removes failed contributions from monthly reports brave-core#5028

Monthly statement after successful AC:

Monthly statement after changing step value in contribution_info table:

Note - as mentioned in brave/brave-core#5028 (comment), confirmed with @NejcZdovc that the Auto Contribute will still show in the summary (upper right corner) of monthly statement as well as on panel and brave://rewards summaries.

Verification passed on

Brave	1.7.79 Chromium: 80.0.3987.149 (Official Build) dev (64-bit)
Revision	5f4eb224680e5d7dca88504586e9fd951840cac6-refs/branch-heads/3987_137@{#16}
OS	Windows 10 OS Version 1803 (Build 17134.1006)

Monthly statement after successful AC:

Monthly statement after changing step value in contribution_info table:

Rewards summary in brave://rewards settings page and BR Panel remains as it is

Verification passed on

Brave	1.7.81 Chromium: 80.0.3987.149 (Official Build) dev (64-bit)
Revision	5f4eb224680e5d7dca88504586e9fd951840cac6-refs/branch-heads/3987_137@{#16}
OS	Ubuntu 18.04 LTS

• Verified test plan from Removes failed contributions from monthly reports brave-core#5028

Monthly statement after successful AC:

Monthly statement after changing step value in contribution_info table: