t7401: change indentation for enhanced readability

t7401: change indentation for enhanced readability

Change the indentation of expected outputs for enhanced readability of
the tests. Also modify the heredoc string limiter in a test which lacks
it to support the indentation change.

Mentored-by: Christian Couder <redacted>
Mentored-by: Kaartic Sivaraam <redacted>
Helped-by: Junio C Hamano <redacted>
Helped-by: Taylor Blau <redacted>
Signed-off-by: Shourya Shukla <redacted>
Signed-off-by: Junio C Hamano <redacted>