Ensure plurality in backfill count message with more than 1 run. #3766

Job	Run time
Build info	31s
Summarize warnings	0s
Basic tests / Breeze unit tests	1m 26s
Build CI images	0s
Basic tests / React UI tests	1m 28s
Basic tests / Install pre-commit for cache	55s
Basic tests / Test git clone on Windows	19s
Basic tests / Test Airflow release commands	0s
provider distributions tests	0s
Additional CI image checks	0s
Sqlite tests: providers	0s
Integration and System Tests	0s
Generate constraints	0s
Non-DB tests: providers	0s
CI image checks	0s
Task SDK tests	0s
MySQL tests: providers	0s
Postgres tests: core	0s
Postgres tests: providers	0s
Low dep tests:core	0s
Sqlite tests: core	0s
Go SDK tests	0s
Airflow CTL tests	0s
Low dep tests: providers	0s
MySQL tests: core	0s
Non-DB tests: core	0s
Build PROD images	0s
Special tests	0s
Helm tests	0s
Kubernetes tests	0s
Additional PROD image tests	0s
Basic tests / Static checks: basic checks only	4m 21s
Basic tests / Upgrade checks	-1s
Finalize tests / Update constraints	-1s
Notify Slack on Failure	0s
Finalize tests / Push Regular Image Cache linux/amd64	-1s
	8m 57s

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