chore: sync WebMCP test expectations from upstream PR #14918 (#3450)

Adds the three PASS expectations upstream added in puppeteer/puppeteer#14918
(toolinvoked, toolresponded with errorText, toolresponded with exception)
to TestExpectations.upstream.json. Chrome itself was already rolled past
148.0.7778.56 by PR #3446 (148.0.7778.97), and the TS pragma removals in
WebMCP.ts have no PuppeteerSharp equivalent.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: kblok

lib/PuppeteerSharp.Nunit/TestExpectations/TestExpectations.upstream.json

@@ -4765,6 +4765,51 @@
     ],
     "comment": "Experimental support for WebMCP requires Chrome 149+."
   },
+  {
+    "testIdPattern": "[webmcp.spec] Page.webmcp should fire toolinvoked events",
+    "platforms": [
+      "darwin",
+      "linux",
+      "win32"
+    ],
+    "parameters": [
+      "cdp",
+      "chrome"
+    ],
+    "expectations": [
+      "PASS"
+    ]
+  },
+  {
+    "testIdPattern": "[webmcp.spec] Page.webmcp should fire toolresponded event with errorText",
+    "platforms": [
+      "darwin",
+      "linux",
+      "win32"
+    ],
+    "parameters": [
+      "cdp",
+      "chrome"
+    ],
+    "expectations": [
+      "PASS"
+    ]
+  },
+  {
+    "testIdPattern": "[webmcp.spec] Page.webmcp should fire toolresponded event with exception",
+    "platforms": [
+      "darwin",
+      "linux",
+      "win32"
+    ],
+    "parameters": [
+      "cdp",
+      "chrome"
+    ],
+    "expectations": [
+      "PASS"
+    ]
+  },
   {
     "testIdPattern": "[webmcp.spec] Page.webmcp should remove tools on frame navigation",
     "platforms": [