Chore: avoid git submodule errors when publishing API docs

[georgesittas]

The git submodule appears to cause some issues when publishing the API docs page: https://github.com/tobymao/sqlglot/actions/runs/24682456936/job/72182993316. This PR tries to fix that issue.

[github-actions]

SQLGlot Integration Test Results

Comparing:

• this branch (sqlglot:jo/fix_api_docs_publish_job, sqlglot version: jo/fix_api_docs_publish_job)
• baseline (main, sqlglot version: 0.0.1.dev1)

By Dialect

dialect	main	sqlglot:jo/fix_api_docs_publish_job	transitions	links
bigquery -> bigquery	24643/24648 passed (100.0%)	23493/23493 passed (100.0%)	No change	full result / delta
bigquery -> duckdb	867/1154 passed (75.1%)	0/0 passed (0.0%)	Results not found	full result / delta
duckdb -> duckdb	5823/5823 passed (100.0%)	0/0 passed (0.0%)	Results not found	full result / delta
snowflake -> duckdb	1063/1961 passed (54.2%)	0/0 passed (0.0%)	Results not found	full result / delta
snowflake -> snowflake	65133/65133 passed (100.0%)	63027/63027 passed (100.0%)	No change	full result / delta
databricks -> databricks	1370/1370 passed (100.0%)	1370/1370 passed (100.0%)	No change	full result / delta
postgres -> postgres	6042/6042 passed (100.0%)	6042/6042 passed (100.0%)	No change	full result / delta
redshift -> redshift	7101/7101 passed (100.0%)	7101/7101 passed (100.0%)	No change	full result / delta

Overall

main: 113232 total, 112042 passed (pass rate: 98.9%), sqlglot version: 0.0.1.dev1

sqlglot:jo/fix_api_docs_publish_job: 101033 total, 101033 passed (pass rate: 100.0%), sqlglot version: jo/fix_api_docs_publish_job

Transitions:
No change

Dialect pair changes: 0 previous results not found, 3 current results not found

✅ 31 test(s) passed