Not including wallet providers for 3p iframes breaks ImmutableX

[bbondy]

Reverting brave/brave-core#13268 locally fixes the problem.
Introduced by issue #22686

Steps to reproduce:

1. Go to https://market.immutable.com/
2. Try to connect your wallet

Actual results:
No wallet detected error shows up

Expected results:
It pops up Brave Wallet

I did some logging:

diff --git a/renderer/brave_wallet/brave_wallet_render_frame_observer.cc b/renderer/brave_wallet/brave_wallet_render_frame_observer.cc
index 9e219ace5a..ecb06b78bb 100644
--- a/renderer/brave_wallet/brave_wallet_render_frame_observer.cc
+++ b/renderer/brave_wallet/brave_wallet_render_frame_observer.cc
@@ -45,6 +45,11 @@ void BraveWalletRenderFrameObserver::DidCreateScriptContext(
     js_ethereum_provider_.reset();
     return;
   }
+
+  LOG(ERROR) << "====top security origin: " << url::Origin(render_frame()->GetWebFrame()->Top()->GetSecurityOrigin()).GetURL();
+  LOG(ERROR) << "====security origin: " << url::Origin(render_frame()->GetWebFrame()->GetSecurityOrigin()).GetURL();
+

And get:

[70565:259:0530/105109.057027:ERROR:brave_wallet_render_frame_observer.cc(50)] ====top security origin: https://market.immutable.com/
[70565:259:0530/105109.070682:ERROR:brave_wallet_render_frame_observer.cc(51)] ====security origin: https://akuma.immutable.com/

[bbondy]

Connect https://link.x.immutable.com
Sign: https://link.x.immutable.com

Modify hosts file to have:
127.0.0.1 z.com
127.0.0.1 y.z.com
127.0.0.1 y.com

Note: Granting permission on z.com does not give you permission on y.z.com and vice versa. They are treated differently. The below is only for what is allowed to prompt for permission.

I break down how it works into 3 sections:

1. What we used to do (which also matches what MetaMask currently does).
2. What we changed to in 1.39.x
3. What I want it to do for webcompat

Original Brave (before 1.39.x) and Current MetaMask:

Test case 1)
Top level load: z.com
iframes of:

1. Same context:
 Can request permission
2. z.com 
Can request permission
3. y.z.com 
Can request permission
4. y.com 
Can request permission

Test case 2)
Top level load: y.z.com
iframes of:

1. Same context
: Can request permission
2. z.com
 Can request permission
3. y.z.com 
Can request permission
4. y.com
 Can request permission
   


---

1.39.x (current release)

Test case 1)
Top level load: z.com
iframes of:

1. Same context:
 Can request permission
2. z.com
 Can request permission
3. y.z.com
 Cannot request permission (no window.ethereum exists)
4. y.com 
Cannot request permission (no window.ethereum exists)

Test case 2)
Top level load: y.z.com
iframes of:

1. Same context
: Can request permission
2. z.com
 Cannot request permission (no window.ethereum exists)
3. y.z.com
 Can request permission
4. y.com
 Cannot request permission (no window.ethereum exists)

---

With implemented changes

Test case 1)
Top level load: z.com
iframes of:

1. Same context:
 Can request permission
2. z.com 
Can request permission
3. y.z.com 
Can request permission
4. y.com 
Cannot request permission (no window.ethereum exists)

Test case 2)
Top level load: y.z.com
iframes of:

1. Same context: 
Can request permission
2. z.com 
Can request permission
3. y.z.com 
Can request permission
4. y.com 
Cannot request permission (no window.ethereum exists)

[bbondy]

No longer valid with brave/brave-core#13783