Update toml to v1

[jakubadamw]

Updates the toml dependency to v1 and addresses any changes needed in the code and test expectations.

changelog: none

[rustbot]

r? @Jarcho

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The reviewer was selected based on:

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[rustbot]

This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.