fix: Add batch delete and cancel support for flow runs

[hemantmm]

closes: #19904

Adds support for batch operations for flow runs by allowing multiple flow run IDs to be passed to the CLI commands.

Before:
prefect flow-run delete id1
prefect flow-run delete id2
prefect flow-run delete id3

After:
prefect flow-run delete id1 id2 id3

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Honor --stdin before reading standard input

When prefect flow-run cancel <id> is run from an interactive terminal without --stdin, sys.stdin is still truthy, so this loop waits for EOF before any cancellation occurs; with piped input it also consumes and parses unrelated stdin as UUIDs. Gate this block on the stdin option, matching the new delete command behavior, so the normal cancellation path does not block or read unexpected input.

Useful? React with 👍 / 👎.

[codspeed-hq]

Merging this PR will not alter performance

✅ 8 untouched benchmarks
⏩ 1 skipped benchmark¹

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_{Comparing hemantmm:flow-run-batch-delete-cancel (5a1619d) with main (e948a74)}

Footnotes

1. 1 benchmark was skipped, so the baseline result was used instead. If it was deleted from the codebase, click here and archive it to remove it from the performance reports. ↩

[hemantmm]

@desertaxle, can you review this PR?