[mercury][dialog] Remove --ch-dialog-max-inline-size from the dialog element

[bsastregx]

Changes in this PR:

Mercury

• Remove --ch-dialog-max-inline-size variable defined at the dialogelement. This variable was duplicated, and it should only be defined at the host context.

before:

.dialog {
  --ch-dialog-max-block-size: 600px;
  --ch-dialog-max-inline-size: 800px;
  --ch-dialog-min-block-size: 200px;
  --ch-dialog-min-inline-size: 300px;
}
.dialog::part(dialog) {
  --ch-dialog-max-inline-size: 800px; /* duplicated */
}

after:

.dialog {
  --ch-dialog-max-block-size: 600px;
  --ch-dialog-max-inline-size: 800px;
  --ch-dialog-min-block-size: 200px;
  --ch-dialog-min-inline-size: 300px;
}