Update runtime to GNOME 46

[darkdragon-001]

GNOME 44 is EOL.

[flathubbot]

Started test build 125210

[flathubbot]

Build 125210 failed

[darkdragon-001]

@theironrobin the appstream file needs an update:

{
    "errors": [
        "appstream-failed-validation"
    ],
    "warnings": [
        "desktop-file-low-quality-category",
        "appstream-screenshot-missing-caption"
    ],
    "appstream": [
        "W: com.github.theironrobin.siglo.desktop:23: screenshot-default-missing",
        "E: com.github.theironrobin.siglo.desktop:44: custom-key-duplicated Purism::form_factor",
        "E: com.github.theironrobin.siglo.desktop:13: description-para-markup-invalid ul",
        "E: com.github.theironrobin.siglo.desktop:~: desktop-app-launchable-omitted"
    ],
    "message": "Please consult the documentation at https://docs.flathub.org/docs/for-app-authors/linter"
}