Unwanted detection of SVG elements in foreign namespace

[halfnelson]

Describe the bug
When using a foreign namespace, svelte is detecting some elements as SVG which changes is handling of the elements including lower casing the attributes. Expected behaviour would be to skip special SVG handling when in a foreign namespace.

This has hit svelte-nodegui which has an element called 'view' which is triggering svelte to place it in the SVG namespace and force attributes to match SVG case ( nodegui/svelte-nodegui#43 )

<svelte:options namespace="foreign" />
<window>
    <view class="vertical">

	window_1 = document.createElementNS("https://svelte.dev/docs#svelte_options", "window");
	view2 = svg_element("view");
	view0 = svg_element("view");
	text0 = svg_element("text");

To Reproduce

REPL: https://svelte.dev/repl/a64f21f99f3d48de992a731a76818c32?version=3.37.0

Expected behavior
all elements should be treated as foreign namespace (unless they have an xmlns attribute)

Severity
This is blocking users of svelte-nodegui from using certain attributes like readOnly and wordWrap

[halfnelson]

https://github.com/sveltejs/svelte/blob/master/src/compiler/compile/nodes/Element.ts#L110 looks like the culprit

	if (!parent_element) {
		return explicit_namespace || (svg.test(element.name)
			? namespaces.svg
			: null);
	}

	if (svg.test(element.name.toLowerCase())) return namespaces.svg;
	if (parent_element.name.toLowerCase() === 'foreignobject') return null;

	return parent_element.namespace;

Top level elements get the explicit_namespace, but child elements get forced to svg if they match the svg element regex

[Conduitry]

Your fix for this has been included in 3.38.0 - thanks!