refactor(tsdb): use models.Empty as deleted SeriesID's FieldType

[zhulongcheng]

Closes #

Describe your proposed changes here. Actually, id.WithType(0) convert the SeriesID to Integer SeriesIDTyped.

Use models.Empty as deleted SeriesID's FieldType, to consistent with tombstone entry :

https://github.com/influxdata/influxdb/blob/530ceb9cbdae077302f37201bf3ef6cb8192e4fc/tsdb/series_partition.go#L364-L370

• [x] CHANGELOG.md updated with a link to the PR (not the Issue)
• [ ] Well-formatted commit messages
• [x] Rebased/mergeable
• [x] Tests pass
• [x] http/swagger.yml updated (if modified Go structs or API)
• [x] Documentation updated or issue created (provide link to issue/pr)
• [x] Signed CLA (if not already signed)

[zhulongcheng]

ping @e-dard

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This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[e-dard]

@zhulongcheng thanks for this. I'm going to need to find some time to review it more carefully. Not sure when that will be though.