test_download_remote_layers_api: try to make less flaky

the size comparisons in this test are quite much.

test_runner/regress/test_ondemand_download.py

@@ -396,9 +396,19 @@ def get_resident_physical_size():
     wait_until(10, 0.2, lambda: assert_tenant_state(client, tenant_id, "Active"))
 
     ###### Phase 1: exercise download error code path
+
+    # comparison here is requiring the size to be at least the previous size, because it's possible received WAL after last_flush_lsn_upload
+    # witnessed for example difference of 29827072 (filled_current_physical) to 29868032 (here) is no good reason to fail a test.
+    this_time = get_api_current_physical_size()
     assert (
-        filled_current_physical == get_api_current_physical_size()
+        filled_current_physical <= this_time
     ), "current_physical_size is sum of loaded layer sizes, independent of whether local or remote"
+    if filled_current_physical != this_time:
+        log.info(
+            f"fixing up filled_current_physical from {filled_current_physical} to {this_time} ({this_time - filled_current_physical})"
+        )
+        filled_current_physical = this_time
+
     post_unlink_size = get_resident_physical_size()
     log.info(f"post_unlink_size: {post_unlink_size}")
     assert (