Update server description

[LiamConnors]

Type was changed here https://github.com/plotly/dash/pull/3430/changes#diff-187d1883eb8273e47c7fae609bb5667d5a9488f9406dfc6a9ca5f19d8d7cc205L438

Closes #3623

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Contributor Checklist

• I have broken down my PR scope into the following TODO tasks
  • task 1
  • task 2
• I have run the tests locally and they passed. (refer to testing section in contributing)
• I have added tests, or extended existing tests, to cover any new features or bugs fixed in this PR

optionals

• I have added entry in the CHANGELOG.md
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  • this GitHub #PR number updates the dash docs
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[github-actions]

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This PR is exempt from requiring a linked issue due to its labels.

[T4rk1n]

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