Remove try without catch.

The Scala 3 compiler reports a warning:

```scala
-- [E002] Syntax Warning: /Users/matt/scalasql/scalasql/core/src/DbApi.scala:205:8
205 |        try {
    |        ^
    |        A try without catch or finally is equivalent to putting
    |        its body in a block; no exceptions are handled.
206 |          val res = stream(query, fetchSize, queryTimeoutSeconds)(
207 |            qr.asInstanceOf[Queryable[Q, Seq[_]]],
208 |            fileName,
209 |            lineNum
210 |          )
211 |          if (qr.isSingleRow(query)) {
212 |            val results = res.take(2).toVector
213 |            assert(
214 |              results.size == 1,
215 |              s"Single row query must return 1 result, not ${results.size}"
216 |            )
217 |            results.head.asInstanceOf[R]
218 |          } else {
219 |            res.toVector.asInstanceOf[R]
220 |          }
221 |        }
```

scalasql/core/src/DbApi.scala

@@ -202,22 +202,20 @@ object DbApi {
           .asInstanceOf[R]
       else if (qr.isExecuteUpdate(query)) updateSql(flattened).asInstanceOf[R]
       else {
-        try {
-          val res = stream(query, fetchSize, queryTimeoutSeconds)(
-            qr.asInstanceOf[Queryable[Q, Seq[_]]],
-            fileName,
-            lineNum
+        val res = stream(query, fetchSize, queryTimeoutSeconds)(
+          qr.asInstanceOf[Queryable[Q, Seq[_]]],
+          fileName,
+          lineNum
+        )
+        if (qr.isSingleRow(query)) {
+          val results = res.take(2).toVector
+          assert(
+            results.size == 1,
+            s"Single row query must return 1 result, not ${results.size}"
           )
-          if (qr.isSingleRow(query)) {
-            val results = res.take(2).toVector
-            assert(
-              results.size == 1,
-              s"Single row query must return 1 result, not ${results.size}"
-            )
-            results.head.asInstanceOf[R]
-          } else {
-            res.toVector.asInstanceOf[R]
-          }
+          results.head.asInstanceOf[R]
+        } else {
+          res.toVector.asInstanceOf[R]
         }
       }
     }