SVG `<title>` element in `{#if ...}` block rendered with wrong `namespaceURI`

[bdpartridge]

Describe the bug

When an SVG element is rendered in an {#if ...} block, it's created in the wrong namespace, which can break certain behaviors. See the link below for a reproduction of the issue. The second icon is rendered with a <title> to give the SVG image an accessible name, but it doesn't work because it has the wrong namespaceURI.

Reproduction

https://svelte.dev/playground/hello-world?version=5.15.0#H4sIAAAAAAAAE3VSTY_TMBD9K6OBA0iNY7f53rQI9oCQ4ITEBXMIrttY6zpR4ra7W-W_IzspJcAqyuS9-XozmlzQVAeJBX799hHOytYgGrNVVjWm0mCV1RIXuFNa9lh8v6B9al22c-DiWvu-bUl_kto638-ql__zi8ZYaWyPBZa96FRrN9xwqw5t01n4JBoDu645AEcSOjZVcrzjpgxvFab0ueHmivyQa473qhNaTkvUUjwcqu6Bo8_EBVr5aLGw3VEOixf2-EN2vsg88MImWlq4-GEGWMPrtmva_s3bf6bvT3s4KXn-0DyuOVKgwBJgCUeoOlUFtdpupVmPjeAdmKPWUABHNznHwUtdXqnduPfgKLelJ5tJvgxH6lNDtfNJZVvZGrZrjl8yoPcrEmc5OPkryvoRZeMTTCyYUOBQ9nygwGIRrEiWAA3SYEVYFKRB2o8AUveCI-DICJzvmeOmDN0Qm7_GYYywKIGYrLLsc0LybAk5ieMlRCRb5ZCSiOYiICyPJxOz5YRSmgL1-HfYRYGCC-klifIEvBXXJBf3X1-rIxKzLPBW3HpcZVzzlKZzcXYTJ5Sy2WJl2J_206Ht03QDd_LLeKiz2tq6AJa0j3ejp5ZqX9uZa6e0LkAcu04aKxrddD4w-PZT1_kf_WP4BYC8LjLJAwAA

Logs

No response

System Info

Svelte 5.15.0

Severity

blocking an upgrade