fix(cicd): chunk bot messages on character boundaries #3911

Job	Run time
changes	6s
test-dbt-versions (1.5)	1m 29s
test-dbt-versions (1.8)	1m 39s
test-dbt-versions (1.6)	1m 38s
test-dbt-versions (1.4)	1m 39s
test-dbt-versions (1.9)	1m 50s
test-dbt-versions (1.10)	1m 36s
test-dbt-versions (1.7)	1m 42s
test-dbt-versions (1.3)	1m 52s
test-vscode	-1s
test-vscode-e2e	-1s
cicd-tests-windows	9m 54s
doc-tests	32s
migration-test	1m 29s
style-and-cicd-tests (3.12)	25m 2s
style-and-cicd-tests (3.13)	23m 44s
style-and-cicd-tests (3.9)	25m 4s
style-and-cicd-tests (3.10)	23m 8s
style-and-cicd-tests (3.11)	23m 23s
engine-tests-docker (duckdb)	1m 33s
engine-tests-docker (mssql)	1m 53s
engine-tests-docker (spark)	5m 18s
engine-tests-docker (clickhouse)	2m 46s
engine-tests-docker (postgres)	2m 10s
engine-tests-docker (risingwave)	2m 55s
engine-tests-docker (trino)	8m 28s
engine-tests-docker (starrocks)	2m 34s
engine-tests-docker (mysql)	1m 59s
ui-style	0s
ui-test	-1s
engine-tests-cloud	0s
	2h 55m 20s

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