slot forwarding: forwards missing slots as "empty" slots

[alf5]

Describe the bug

When doing slot forwarding e.g. <slot name="x" slot="x"/>, with no incoming slot of that name, an "empty" slot is forwarded.
Where what should happen (IMHO) is that NO slot should be forwarded therefore allowing the receiving component to render the default content.

Reproduction

Svelte Repl

Logs

No response

System Info

System:
    OS: Linux 5.18 Ubuntu 22.04.2 LTS 22.04.2 LTS (Jammy Jellyfish)
    CPU: (16) x64 AMD Ryzen 7 5700G with Radeon Graphics
    Memory: 23.11 GB / 30.75 GB
    Container: Yes
    Shell: 5.8.1 - /usr/bin/zsh
  Binaries:
    Node: 18.16.0 - ~/.local/share/pnpm/node
    npm: 9.5.1 - ~/.local/share/pnpm/npm
    pnpm: 8.6.10 - ~/.local/share/pnpm/pnpm
  Browsers:
    Chrome: 115.0.5790.110
  npmPackages:
    svelte: ^4.1.1 => 4.1.1

Severity

annoyance

[gtm-nayan]

Closing as duplicate of #6059