Simplify mcp.run example by removing json_response #371

Job	Run time
checks / pre-commit	32s
checks / readme-snippets	9s
checks / test (3.10, lowest-direct, windows-latest)	2m 39s
checks / test (3.10, locked, ubuntu-latest)	48s
checks / test (3.11, lowest-direct, ubuntu-latest)	51s
checks / test (3.12, lowest-direct, ubuntu-latest)	53s
checks / test (3.12, locked, ubuntu-latest)	52s
checks / test (3.11, locked, windows-latest)	2m 46s
checks / test (3.10, locked, windows-latest)	2m 48s
checks / test (3.12, locked, windows-latest)	3m 23s
checks / test (3.12, lowest-direct, windows-latest)	3m 44s
checks / test (3.10, lowest-direct, ubuntu-latest)	50s
checks / test (3.11, locked, ubuntu-latest)	48s
checks / test (3.13, lowest-direct, ubuntu-latest)	50s
checks / test (3.13, lowest-direct, windows-latest)	2m 36s
checks / test (3.13, locked, ubuntu-latest)	48s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 16s
checks / test (3.14, lowest-direct, windows-latest)	2m 45s
checks / test (3.14, locked, ubuntu-latest)	2m 21s
checks / test (3.11, lowest-direct, windows-latest)	2m 53s
checks / test (3.14, locked, windows-latest)	3m 18s
checks / test (3.13, locked, windows-latest)	2m 18s
all-green	3s
	40m 11s

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