TEC-632: OXD list table skeleton improvements and fixes

[dilansisitha1]

Checklist

• Test Coverage is 100% for the newly added code
• Storybook stories are added/updated for the changed areas
• Components standards defined in this document are followed
• Code is linted properly
• Developer testing is done for the affected areas
• Package version updated (not applicable to ent branch)
• Changelog.md updated on possible breaking (applicable to ent branch)

[Super-Chama]

const cardHeaders = computed(() => {
  if (props.loading && props.skeleton) {
    return [
      {
        name: "selector",
        cellType: "oxd-table-cell-checkbox",
      },
      ...props.headers.filter(
        (header) => header.name !== "action" && !header.title
      ),
    ];
  }
  if (props.selectable) {
    return [
      {
        name: "selector",
        cellType: "oxd-table-cell-checkbox",
      },
      ...headers,
    ];
  }

  return props.headers;
});

Consider this refactoring rather than using computedHeaders

[dilansisitha1]

computedHeaders and cardHeaders has two different behaviors.