Remove svelte/html-self-closing in the future

[baseballyama]

https://sveltejs.github.io/eslint-plugin-svelte/rules/html-closing-bracket-spacing/

Currently, Svelte 5 determines whether a tag is self-closing based on whether it is a void element and issues warnings accordingly. This enforces correct HTML syntax. Therefore, I believe there is no longer a need to provide a rule for this in ESLint.
sveltejs/svelte#11114

However, this rule is still necessary for certain cases, such as <Component>.

[baseballyama]

Upon further investigation, it seems that the proper course of action is to improve the implementation of the rule.

[ota-meshi]

Yeah, I think we probably need to change the default behavior of the rule.
I think the current default options are based on the old prettier-svelte plugin, but should now be changed to the new defaults.