allow adding same components multiple times in 'sequence' using blocks

[hilsonshrestha]

Does this PR close any open issues?

Closes #1029

Give a longer description of what this PR addresses and why it's needed

Currently, same component cannot be added twice in sequence restricting us to reuse components. This also applied to libraries.
This PR allows same component name to be in the sequence by separating into blocks.

Example:

{
    "components": [
      "introduction",
      "$demographics.components.demographics",
      "barChart",
      {
        "id": "block1",
        "order": "fixed",
        "components": ["barChart"]
      },
      {
        "id": "block2",
        "order": "fixed",
        "components": ["barChart"]
      },
      {
        "id": "block3",
        "order": "fixed",
        "components": ["$demographics.components.demographics"]
      },
      {
        "id": "block4",
        "order": "fixed",
        "components": ["$demographics.components.demographics"]
      },
      {
        "id": "block5",
        "order": "fixed",
        "components": [
          {
            "order": "fixed",
            "id": "block5-1",
            "components": ["$demographics.components.demographics"]
          }
        ]
      },
      "external_website"
    ]
}

[github-actions]

A preview of is uploaded and can be seen here:

✨ https://revisit.dev/study/PR1050 ✨

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