adapter: Always set primary export of sources

Previously, when `force_source_table_syntax` was enabled, the primary
export of sources was disabled. This feature was never tested and did
not work. This commit reverts this feature so that the primary export
is always created.

src/sql/src/plan/statement/ddl.rs

@@ -1040,13 +1040,10 @@ pub fn plan_create_source(
         // We only define primary-export details for this source if we are still supporting
         // the legacy source syntax. Otherwise, we will not output to the primary collection.
         // TODO(database-issues#8620): Remove this field once the new syntax is enabled everywhere
-        primary_export: match force_source_table_syntax {
-            false => Some(SourceExportDataConfig {
-                encoding,
-                envelope: envelope.clone(),
-            }),
-            true => None,
-        },
+        primary_export: Some(SourceExportDataConfig {
+            encoding,
+            envelope: envelope.clone(),
+        }),
         timestamp_interval,
     };
 

src/storage-types/src/sources.rs

@@ -833,6 +833,8 @@ pub struct SourceDesc<C: ConnectionAccess = InlinedConnection> {
     /// primary collection for this source.
     /// TODO(database-issues#8620): This will be removed once sources no longer export
     /// to primary collections and only export to explicit SourceExports (tables).
+    /// The value for this is ALWAYS `Some`, because we couldn't figure out how to get
+    /// `None` to work.
     pub primary_export: Option<SourceExportDataConfig<C>>,
 }