Refactor Snowflake to avoid brakeman sql injection warnings (#25879)

config/brakeman.ignore

@@ -79,29 +79,6 @@
       ],
       "note": ""
     },
-    {
-      "warning_type": "SQL Injection",
-      "warning_code": 0,
-      "fingerprint": "75fcd147b7611763ab6915faf8c5b0709e612b460f27c05c72d8b9bd0a6a77f8",
-      "check_name": "SQL",
-      "message": "Possible SQL injection",
-      "file": "lib/mastodon/snowflake.rb",
-      "line": 87,
-      "link": "https://brakemanscanner.org/docs/warning_types/sql_injection/",
-      "code": "connection.execute(\"CREATE OR REPLACE FUNCTION timestamp_id(table_name text)\\nRETURNS bigint AS\\n$$\\n  DECLARE\\n    time_part bigint;\\n    sequence_base bigint;\\n    tail bigint;\\n  BEGIN\\n    time_part := (\\n      -- Get the time in milliseconds\\n      ((date_part('epoch', now()) * 1000))::bigint\\n      -- And shift it over two bytes\\n      << 16);\\n\\n    sequence_base := (\\n      'x' ||\\n      -- Take the first two bytes (four hex characters)\\n      substr(\\n        -- Of the MD5 hash of the data we documented\\n        md5(table_name || '#{SecureRandom.hex(16)}' || time_part::text),\\n        1, 4\\n      )\\n    -- And turn it into a bigint\\n    )::bit(16)::bigint;\\n\\n    -- Finally, add our sequence number to our base, and chop\\n    -- it to the last two bytes\\n    tail := (\\n      (sequence_base + nextval(table_name || '_id_seq'))\\n      & 65535);\\n\\n    -- Return the time part and the sequence part. OR appears\\n    -- faster here than addition, but they're equivalent:\\n    -- time_part has no trailing two bytes, and tail is only\\n    -- the last two bytes.\\n    RETURN time_part | tail;\\n  END\\n$$ LANGUAGE plpgsql VOLATILE;\\n\")",
-      "render_path": null,
-      "location": {
-        "type": "method",
-        "class": "Mastodon::Snowflake",
-        "method": "define_timestamp_id"
-      },
-      "user_input": "SecureRandom.hex(16)",
-      "confidence": "Medium",
-      "cwe_id": [
-        89
-      ],
-      "note": ""
-    },
     {
       "warning_type": "Denial of Service",
       "warning_code": 76,