fix: Update get missing block

main.py

@@ -259,22 +259,22 @@ def getNodeHeight():
     info = response.json()
     return info["chain"]["height"]
 
-
-def getFirstMissingBlock():
-    """Finds missing block heights in the database."""
-    height = dbGet.execute("SELECT height FROM blocks ORDER BY height ASC")
-    heights = [row[0] for row in height]
+def getFirstMissingBlock() -> int:
+    """Finds the first missing block height in the database."""
+    
+    # Fetch all existing block heights in ascending order
+    result = dbGet.query("SELECT height FROM blocks ORDER BY height ASC").result
+    heights = [row[0] for row in result]
 
     if not heights:
-        return 0
+        return 0  # No blocks found, start from 0
 
-    block = 0
-    for i in heights:
-        if i == block:
-            block += 1
-        else:
-            return block
-    return block
+    # Find the first missing block height
+    for expected, actual in enumerate(heights):
+        if expected != actual:
+            return expected  # First missing height found
+
+    return len(heights)  # No missing block, return next expected height
 
 
 async def main():