fix(cli): coerce plan --min-intervals to int #4029

Job	Run time
changes	5s
test-dbt-versions (1.9)	1m 49s
test-dbt-versions (1.7)	1m 47s
test-dbt-versions (1.10)	1m 48s
test-dbt-versions (1.8)	1m 36s
test-dbt-versions (1.5)	1m 30s
test-dbt-versions (1.4)	1m 26s
test-dbt-versions (1.6)	1m 34s
test-dbt-versions (1.3)	1m 43s
test-vscode-e2e	0s
test-vscode	0s
cicd-tests-windows	12m 30s
doc-tests	35s
migration-test	1m 35s
style-and-cicd-tests (3.9)	18m 8s
style-and-cicd-tests (3.11)	23m 25s
style-and-cicd-tests (3.13)	23m 55s
style-and-cicd-tests (3.12)	20m 57s
style-and-cicd-tests (3.10)	23m 55s
engine-tests-docker (trino)	8m 14s
engine-tests-docker (clickhouse)	2m 46s
engine-tests-docker (duckdb)	1m 45s
engine-tests-docker (postgres)	2m 25s
engine-tests-docker (spark)	5m 10s
engine-tests-docker (risingwave)	2m 34s
engine-tests-docker (mssql)	1m 45s
engine-tests-docker (starrocks)	2m 22s
ui-test	0s
engine-tests-docker (mysql)	1m 48s
ui-style	0s
engine-tests-cloud	0s
	2h 47m 7s

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