Fix custom Brave notification ads should be attached to the browser window

[btlechowski]

Follow up to #19464.
On Windows the custom ad notification is not anchored to Brave Window so the z-ordering does not work, the ad stays on top.

Steps to Reproduce

1. Clean install
2. Run Brave with: --enable-logging=stderr --vmodule="*/variations/*"=6,"*/bat-native-ledger/*"=6,"*/brave_rewards/*"=6,"*/bat-native-ads/*"=6,"*/bat-native-confirmations/*"=6,"*/brave_ads/*"=9,"*/brave_user_model/*"=6,"*/bat_ads/*"=6 --brave-ads-staging --rewards=staging=true --variations-server-url=https://v --enable-features="CustomAdNotifications:should_attach_ad_notification_to_browser_window/true"
3. Enable rewards and ads
4. Trigger a notification ad

Actual result:

Notification ad is not anchored to the browser window, the ad stays on top

Expected result:

Notification ad is anchored to the browser window

Reproduces how often:

Easily reproduced

Brave version (brave://version info)

Brave	1.38.83 Chromium: 100.0.4896.79 (Official Build) beta (64-bit)
Revision	8fb749dcab8700c24213791969e59deb72fee36f-refs/branch-heads/4896@{#1015}
OS	Windows 10 Version 21H2 (Build 19044.1586)

cc @brave/qa-team @jsecretan @tmancey @aseren

[btlechowski]

Verification passed on

Brave	1.52.93 Chromium: 113.0.5672.92 (Official Build) beta (64-bit)
Revision	b6f521170062a1fa8a82c33fb223b06fec566da1-refs/branch-heads/5672_63@{#10}
OS	Ubuntu 18.04 LTS

Issue still reproducible. Per our process logged #30508

---

Verification passed on

Brave	1.52.109 Chromium: 114.0.5735.26 (Official Build) beta (64-bit)
Revision	7075cbb66f0542ac3e01ddfde6b813e7d61118a5-refs/branch-heads/5735@{#454}
OS	Windows 10 Version 22H2 (Build 19045.2965)

Verified test plan from the description

[stephendonner]

Verified PASSED using

Brave 1.52.109 Chromium: 114.0.5735.26 (Official Build) beta (x86_64)
Revision 7075cbb66f0542ac3e01ddfde6b813e7d61118a5-refs/branch-heads/5735@{#454}
OS macOS Version 11.7.7 (Build 20G1345)

[aseren]

The parameter name was changed to should_attach_ad_notification_to_browser_window for Beta 1.52. For Nightly version it was renamed to use_same_z_order_as_browser_window and set to true by default: #30508 (comment)

[tmancey]

I will raise an issue to add the latest feature/param/values to a README.md you can access in the repo.

[btlechowski]

Thanks @aseren @tmancey . We will retest with the new parameter.