feat!: revert query limit to be unbounded for scans (#2151)

In earlier PRs (#1886, #1191) we made the default limit 10 regardless of
the query type. This was confusing for users and in many cases a
breaking change. Users would have queries that used to return all
results, but instead only returned the first 10, causing silent bugs.

Part of the cause was consistency: the Python sync API seems to have
always had a limit of 10, while newer APIs (Python async and Nodejs)
didn't.

This PR sets the default limit only for searches (vector search, FTS),
while letting scans (even with filters) be unbounded. It does this
consistently for all SDKs.

Fixes #1983
Fixes #1852
Fixes #2141

python/python/tests/test_fts.py

@@ -174,6 +174,10 @@ def test_search_fts(table, use_tantivy):
     assert len(results) == 5
     assert len(results[0]) == 3  # id, text, _score
 
+    # Default limit of 10
+    results = table.search("puppy").select(["id", "text"]).to_list()
+    assert len(results) == 10
+
 
 @pytest.mark.asyncio
 async def test_fts_select_async(async_table):