Add Origin-Agent-Cluster opt-out for direct-socket tests.

These direct socket tests don't work as WPT tests with Origin Isolation
(kOriginKeyedProcessesByDefault) enabled, since the non-default
port of the test server shows up in the lock_url used to determine
if direct-sockets are allowed or not, and this breaks the tests.
In real-world operation, direct-sockets are used in Chrome apps and
Isolated Web Apps, and neither of these will have non-default ports.
Opting these three tests out via the Origin-Agent-Cluster header
allows them to run in this non-standard test setup.

Bug: 40259221
Change-Id: I7c9349a715005b20ddc48edd5e7813bf749a38c5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5675462
Reviewed-by: Andrew Rayskiy <[email protected]>
Commit-Queue: James Maclean <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1323503}

direct-sockets/disabled-by-permissions-policy.https.sub.html.headers

@@ -1,3 +1,4 @@
 Cross-Origin-Opener-Policy: same-origin
 Cross-Origin-Embedder-Policy: require-corp
 Permissions-Policy: direct-sockets=()
+Origin-Agent-Cluster: ?0

direct-sockets/tcp_socket.https.html.headers

@@ -1,3 +1,4 @@
 Cross-Origin-Opener-Policy: same-origin
 Cross-Origin-Embedder-Policy: require-corp
 Permissions-Policy: direct-sockets=(self)
+Origin-Agent-Cluster: ?0

direct-sockets/udp_socket.https.html.headers

@@ -1,3 +1,4 @@
 Cross-Origin-Opener-Policy: same-origin
 Cross-Origin-Embedder-Policy: require-corp
 Permissions-Policy: direct-sockets=(self)
+Origin-Agent-Cluster: ?0