Implement adding site exceptions to Always clear cookies when tabs are closed

[stephendonner]

Description

Implement adding site exceptions to Always clear cookies when tabs are closed

(There are other open issues requesting the ability to select which item(s) to be cleared on tab close; this is specific to adding exceptions to that feature, once it's in.)

For background, see #15906 (comment)

Steps to reproduce

1. new install
2. launch Brave
3. via brave://flags, enable First Party Ephemeral Storage
4. try to verify Implement 1p Ephemeral Storage Functionality (functionality) #15906 further

Actual result

There's no UI exposed, so I'm unable to add exceptions to sites' tabs using first-party ephemeral storage, on tab close

Expected result

Should be able to add site exceptions via the UI, so that all while other data is cleared on tab close, first-party ephemeral storage persists

Test:

1. new install
2. enable first-party ephemeral storage via brave://flags
3. restart Brave
4. load yandex.com/internet and look for the yandexuid value
5. close the tab
6. load yandex.com/internet again and look for the yandexuid value
7. if the capability to override were present, the values for steps 4 and 6 would be the same. As it stands, without any UI to add the exception to [.]yandex.com which exists on desktop, the value for yandexuid, which is stored in first-party ephemeral storage, changes, as it gets cleared out and regenerated for each tab

It would be the equivalent of this, from desktop:

Issue reproduces how often

100%

Version/Channel Information:

• Can you reproduce this issue with the current Play Store version?
• Can you reproduce this issue with the current Play Store Beta version?
• Can you reproduce this issue with the current Play Store Nightly version?

Device details

• Install type (ARM, x86): arm64
• Device type (Phone, Tablet, Phablet): Google Pixel XL phone
• Android version: 9

Brave version

Brave 1.32.103, Chromium 96.0.4664.45