fix: replace ast.Str and drop astor #3820

Job	Run time
changes	8s
test-dbt-versions (1.6)	1m 45s
test-dbt-versions (1.8)	1m 52s
test-dbt-versions (1.5)	1m 47s
test-dbt-versions (1.10)	1m 34s
test-dbt-versions (1.4)	1m 36s
test-dbt-versions (1.3)	1m 48s
test-dbt-versions (1.7)	1m 50s
test-dbt-versions (1.9)	1m 57s
test-vscode	0s
test-vscode-e2e	0s
doc-tests	41s
cicd-tests-windows	11m 19s
migration-test	1m 1s
style-and-cicd-tests (3.10)	23m 13s
style-and-cicd-tests (3.9)	23m 35s
style-and-cicd-tests (3.11)	22m 17s
style-and-cicd-tests (3.12)	23m 37s
style-and-cicd-tests (3.13)	19m 51s
engine-tests-docker (mysql)	1m 48s
engine-tests-docker (mssql)	2m 19s
engine-tests-docker (duckdb)	1m 42s
engine-tests-docker (postgres)	2m 47s
engine-tests-docker (trino)	9m 29s
engine-tests-docker (clickhouse)	3m 14s
engine-tests-docker (spark)	5m 27s
engine-tests-docker (risingwave)	2m 28s
engine-tests-docker (starrocks)	3m 9s
ui-style	0s
ui-test	0s
engine-tests-cloud	-1s
	2h 52m 13s

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