Use EditInPlace control for Identity Server picker to improve a11y (#29280)

* Use EditInPlace for identity server picker.

* Exclude picker from default dialog button styles.

* Remove unused import.

* Update test

* Remove unused css

* Update test

* drop only

* Add a test for setting an ID server.

* Add a unit test for SetIdServer

* fix tests

* Reformat mx_Dialog button :not list to use a more readable selector.

* Reformat other :not sections

* forgot a comma

* We're in 2025 now.

* Update copyright + use class methods.

res/css/views/settings/_SetIdServer.pcss

@@ -1,23 +0,0 @@
-/*
-Copyright 2024 New Vector Ltd.
-Copyright 2019-2023 The Matrix.org Foundation C.I.C.
-
-SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only OR LicenseRef-Element-Commercial
-Please see LICENSE files in the repository root for full details.
-*/
-
-.mx_SetIdServer {
-    display: flex;
-    flex-direction: column;
-    align-items: flex-start;
-    gap: $spacing-8;
-
-    .mx_Field {
-        width: 100%;
-        margin: 0;
-    }
-}
-
-.mx_SetIdServer_tooltip {
-    max-width: var(--SettingsTab_tooltip-max-width);
-}