fix: multi-playground should use goog.require to get blocks. (#5797)
fix: multi-playground should use goog.require to get blocks. (#5797)


google/blockly,mark-friedman/blockly,rachel-fenichel/blockly,google/blockly,rachel-fenichel/blockly,mark-friedman/blockly,google/blockly,rachel-fenichel/blockly,mark-friedman/blockly,rachel-fenichel/blockly,google/blockly,mark-friedman/blockly,rachel-fenichel/blockly,mark-friedman/blockly,rachel-fenichel/blockly,mark-friedman/blockly,google/blockly,google/blockly,rachel-fenichel/blockly,google/blockly