Fix error submitting run to empty imported fleet #6621

Job	Run time
compute-version	3s
build-docs / build-docs	1m 8s
build-artifacts / runner-test (ubuntu-latest)	1m 16s
build-artifacts / code-lint	53s
build-artifacts / runner-test (macos-latest)	55s
build-artifacts / frontend-build	10s
build-artifacts / gateway-build	11s
build-artifacts / generate-json-schema	21s
build-artifacts / python-build	33s
build-artifacts / python-test (ubuntu-latest, 3.11)	8m 25s
build-artifacts / python-test (ubuntu-latest, 3.10)	9m 9s
build-artifacts / python-test (macos-latest, 3.13)	2m 58s
build-artifacts / python-test (macos-latest, 3.12)	3m 42s
build-artifacts / python-test (windows-latest, 3.10)	2m 14s
build-artifacts / python-test (windows-latest, 3.13)	2m 24s
build-artifacts / python-test (windows-latest, 3.12)	2m 59s
build-artifacts / python-test (macos-latest, 3.10)	3m 1s
build-artifacts / python-test (macos-latest, 3.9)	5m 18s
build-artifacts / python-test (macos-latest, 3.11)	3m 48s
build-artifacts / python-test (ubuntu-latest, 3.9)	7m 35s
build-artifacts / python-test (windows-latest, 3.9)	4m 8s
build-artifacts / python-test (ubuntu-latest, 3.12)	9m 34s
build-artifacts / python-test (ubuntu-latest, 3.13)	8m 27s
build-artifacts / python-test (windows-latest, 3.11)	2m 28s
build-artifacts / runner-compile (ubuntu-24.04-arm, linux, arm64)	32s
build-artifacts / runner-compile (ubuntu-24.04, linux, amd64)	40s
upload-pre-pypi-artifacts / upload-pre-pypi-artifacts	21s
upload-post-pypi-artifacts / upload-post-pypi-artifacts	20s
	1h 23m 33s

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