Adapt OAuth2 implementation to Matrix Spec v1.18 (#34026)

* Adapt OAuth2 implementation to Matrix Spec v1.18

* Handle more cases of oidc->oauth

* Fix test

* Fix read back of oauth2 context

* Iterate

* Fix tests

* Discard changes to apps/web/playwright/e2e/settings/account-user-settings-tab.spec.ts

* Fix test

* Fix test

* Fix test

* Potential fix for pull request finding 'Unused variable, import, function or class'

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* Iterate

* Iterate

* Fix test

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.github/workflows/tests.yml

@@ -119,8 +119,15 @@ jobs:
                   node-version: "lts/*"
                   cache: "pnpm"
 
-            - name: Install Deps
+            - name: Install Deps (layered)
+              run: "./scripts/layered.sh"
+              if: matrix.path != 'packages/shared-components'
+              env:
+                  JS_SDK_GITHUB_BASE_REF: ${{ inputs.matrix-js-sdk-sha }}
+
+            - name: Install Deps (normal)
               run: "pnpm install"
+              if: matrix.path == 'packages/shared-components'
 
             - name: Cache storybook & vitest
               uses: actions/cache@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6