SKU SDK should be able to handle more than one environment

[bsclifton]

Test plan

See brave/brave-core#13852

Description

Right now, if SKU SDK is enabled (behind brave://flags/#skus-sdk flag) - you also need to set an environment flag (brave://flags/#skus-environment)

When this is set, you can only login to that environment because the SKU SDK code will use that hardcoded environment for the incoming calls on the account.brave.software/account.bravesoftware.com/account.brave.com website

Steps to Reproduce

1. Set brave://flags/#skus-sdk flag to enabled
2. Set brave://flags/#skus-environment to development
3. Try to login to https://account.brave.com

Actual result:

Page gets stuck loading

Expected result:

User should be able to login to page

Reproduces how often:

100%

Desktop Brave version:

1.37.33 (Nightly / Desktop / Windows)

[stephendonner]

+1

When someone gets cycles to look at this, it'd be good to take this on, as it would reduce a bit of confusion for testers and dogfooding folks.

[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 13.0 (Build 22A5295i)

Steps:

1. installed 1.42.62
2. launched Brave
3. set brave://flags/#skus-sdk to Enabled
4. restarted Brave
5. loaded, created an account on, and logged in to each of the following environments: development, staging, production

NOTE: brave://flags/#skus-environment is no longer present; it's dynamic, now.

brave://flags/#skus-sdk

development (account.brave.software)	staging (account.bravesoftware.com)	production (account.brave.com)

[Uni-verse]

Verification PASSED on Samsung GS 21 & Tab S7 using

Brave	1.42.80 Chromium: 104.0.5112.57 (Official Build) (64-bit) 
Revision	212fd173a0da1e0a024f328295bb56a2529190bb-refs/branch-heads/5112@{#1042}
OS	Android 12; Build/SP1A.210812.016

Flags:

Mobile	Tablet

Steps:

1. installed 1.42.62
2. launched Brave
3. set brave://flags/#skus-sdk to Enabled
4. restarted Brave
5. loaded, created an account on, and logged in to each of the following environments: development, staging, production

Stage	Dev	Prod

[MadhaviSeelam]

Verification Passed using

Brave | 1.42.78 Chromium: 103.0.5060.134 (Official Build) beta (64-bit)
-- | --
Revision | 8ec6fce403b3feb0869b0732eda8bd95011d333c-refs/branch-heads/5060@{#1262}
OS | Windows 11 Version 21H2 (Build 22000.795)

Steps:

1. installed 1.42.78
2. launched Brave
3. set brave://flags/#skus-sdk to Enabled
4. restarted Brave
5. loaded, created an account on, and logged in to each of the following environments: development, staging, production

NOTE: brave://flags/#skus-environment is no longer present; it's dynamic, now.

brave://flags/#skus-sdk	Ex2	development (account.brave.software)

staging (account.bravesoftware.com)	production (account.brave.com)