[Desktop] in-line tip button missing in certain cases on Reddit

[LaurenWags]

Description

When you're on a post on old.reddit.com such as https://old.reddit.com/r/brave_browser/comments/j7lav2/des_martin_brave_marketing_lead_on_twitter_brave/, the comments/replies to the post display the in-line tip button.

However, if you visit this same post on new reddit (while logged in), the in-line tip button does not display. Note - you must be logged in to reddit as the "toolbar" does not display on the replies/comments if you are not logged in.

note - this reproduces on 1.16.x as well, pre-greaselion.

Steps to Reproduce

1. Clean profile 1.17.x, enable Rewards
2. Visit any post on old reddit, such as the one above
3. See in-line tip icons

4. Visit post on new reddit, note that toolbar is not displayed for the comments

5. Login to Reddit
6. See that the toolbar now displays for the replies/comments but the in-line tip button does not

Actual result:

Expected result:

in-line tip button should be shown

Reproduces how often:

easily

Brave version (brave://version info)

Brave	1.17.52 Chromium: 86.0.4240.111 (Official Build) dev (x86_64)
Revision	b8c36128a06ebad76af51591bfec980224db5522-refs/branch-heads/4240@{#1290}
OS	macOS Version 10.14.6 (Build 18G6032)

Version/Channel Information:

• Can you reproduce this issue with the current release? yes, 1.16.x
• Can you reproduce this issue with the beta channel? yes 1.17.x
• Can you reproduce this issue with the nightly channel? yes 1.18.x

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 @emerick @NejcZdovc