Duplicate tabs shouldn't be possible for Manage subscription flows

[stephendonner]

Description

Duplicate tabs shouldn't be possible for Manage subscription flows

Steps to Reproduce

1. install 1.41.19
2. launch Brave
3. set up VPN
4. click on the VPN button
5. click on the Settings / gear icon
6. click Manage subscription
7. note that https://account.brave.software/ opens up in a new tab
8. repeat 4-7

Actual result:

Duplicate tabs with https://account.brave.software/ keep being opened for each repeated set of the above

example	example	example	example

Expected result:

No duplicate tabs opened with https://account.brave.software/

Reproduces how often:

100%

Brave version (brave://version info)

Brave	1.41.19 Chromium: 102.0.5005.61 (Official Build) nightly (x86_64)
Revision	0e59bcc00cc4985ce39ad31c150065f159d95ad3-refs/branch-heads/5005@{#819}
OS	macOS Version 11.6.6 (Build 20G624)

/cc @simonhong @bsclifton @rebron @nullhook @brave/qa-team

[stephendonner]

Verified PASSED using

Brave	1.42.62 Chromium: 103.0.5060.114 (Official Build) beta (x86_64)
Revision	a1c2360c5b02a6d4d6ab33796ad8a268a6128226-refs/branch-heads/5060@{#1124}
OS	macOS Version 11.6.7 (Build 20G630)

Followed my original steps to reproduce.

Confirmed the initial tab for VPN opens Manage subscription in a single tab.

Filed #24048 because this still happens occasionally (still working on reduced steps) and with a new window

---

Verification PASSED on

Brave | 1.42.78 Chromium: 103.0.5060.134 (Official Build) beta (64-bit)
-- | --
Revision | 8ec6fce403b3feb0869b0732eda8bd95011d333c-refs/branch-heads/5060@{#1262}
OS | Windows 10 Version 21H2 (Build 19044.1826)

• Issue is partially fixed, added comments in Manage Subscription link in about VPN dialog shouldn't open multiple tabs #24048 (comment)