Proxy path fixes (#4548)

* Fix issue where HTTP error status codes are not read.

* Fix issues surrounding sessions when accessed from a proxy.

- Updated vscode args to match latest upstream.
- Fixed issues surrounding trailing slashes affecting base paths.
- Updated cookie names to better match upstream's usage, debuggability.

* Bump vendor.

* Update tests.

* Fix issue where tests lack cookie key.

Co-authored-by: Asher <ash@coder.com>

vendor/package.json

@@ -7,6 +7,6 @@
     "postinstall": "./postinstall.sh"
   },
   "devDependencies": {
-    "code-oss-dev": "cdr/vscode#a1d3f915454bb88e508c269a3c5bafb3cfa6f9f6"
+    "code-oss-dev": "cdr/vscode#5e0c6f3b95ed032e62c49101ae502a46c62ef202"
   }
 }

vendor/yarn.lock

@@ -296,9 +296,9 @@ clone-response@^1.0.2:
   dependencies:
     mimic-response "^1.0.0"
 
-code-oss-dev@cdr/vscode#a1d3f915454bb88e508c269a3c5bafb3cfa6f9f6:
+code-oss-dev@cdr/vscode#5e0c6f3b95ed032e62c49101ae502a46c62ef202:
   version "1.61.1"
-  resolved "https://codeload.github.com/cdr/vscode/tar.gz/a1d3f915454bb88e508c269a3c5bafb3cfa6f9f6"
+  resolved "https://codeload.github.com/cdr/vscode/tar.gz/5e0c6f3b95ed032e62c49101ae502a46c62ef202"
   dependencies:
     "@microsoft/applicationinsights-web" "^2.6.4"
     "@vscode/sqlite3" "4.0.12"