Tipping banner doesn't fit inside the narrow view window

[GeetaSarvadnya]

Description

Found while testing #29815
Tipping banner doesn't fit inside the narrow view window

Steps to Reproduce

1. Clean profile 1.52.x
2. Enable rewards and connect to a custodian
3. Open wikipedia.org in
4. Make the browser window in a narrow view
5. Open the tipping banner for wikipedia page
6. Tipping banner doesn't fit inside the narrow view window

Actual result:

Expected result:

1.51.x

Reproduces how often:

Easy

Brave version (brave://version info)

Brave	1.52.102 Chromium: 113.0.5672.126 (Official Build) beta (64-bit)
Revision	c541687b21a73452ab403e2dced7033ddc97ee9d-refs/branch-heads/5672@{#1202}
OS	Windows 10 Version 21H2 (Build 19044.2965)

Version/Channel Information:

• Can you reproduce this issue with the current release? No
• Can you reproduce this issue with the beta channel? Yes
• Can you reproduce this issue with the nightly channel? Yes

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields? NA
• Does the issue resolve itself when disabling Brave Rewards? NA
• Is the issue reproducible on the latest version of Chrome? NA

Miscellaneous Information:

cc: @brave/qa-team @Miyayes @zenparsing

[Miyayes]

What's causing min-width to be set? Does it even look good if you crunch it up even more?