distsql: add flow ID tag earlier

[yuzefovich]

This allows the tag to be correctly picked up by the asynchronous components (e.g. outboxes) that are created in the Setup method.

Epic: None

Release note: None

[cockroach-teamcity]

This change is 

[andreimatei]

Reviewable status: complete! 1 of 0 LGTMs obtained

[rharding6373]

Reviewable status: complete! 2 of 0 LGTMs obtained

[rharding6373]

Reviewable status: complete! 2 of 0 LGTMs obtained

[yuzefovich]

TFTRs!

bors r+

[craig]

Build succeeded:

• Bazel Essential CI (Cockroach)

[blathers-crl]

Encountered an error creating backports. Some common things that can go wrong:

1. The backport branch might have already existed.
2. There was a merge conflict.
3. The backport branch contained merge commits.

You might need to create your backport manually using the backport tool.

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error creating merge commit from 163dbc0 to blathers/backport-release-22.1-91967: POST https://api.github.com/repos/cockroachdb/cockroach/merges: 409 Merge conflict []

you may need to manually resolve merge conflicts with the backport tool.

Backport to branch 22.1.x failed. See errors above.

---

error creating merge commit from 163dbc0 to blathers/backport-release-22.2-91967: POST https://api.github.com/repos/cockroachdb/cockroach/merges: 409 Merge conflict []

you may need to manually resolve merge conflicts with the backport tool.

Backport to branch 22.2.x failed. See errors above.

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