cubicweb #5460552 avoid use of progress bar in tests when stdout is not a TTY [validation pending]

to avoid things like:

-> creating tables 
-> creating tables  [=                   ]
-> creating tables  [==                  ]
-> creating tables  [===                 ]
-> creating tables  [====                ]
-> creating tables  [=====               ]
-> creating tables  [======              ]
-> creating tables  [=======             ]
-> creating tables  [========            ]
-> creating tables  [=========           ]
-> creating tables  [==========          ]
-> creating tables  [===========         ]
-> creating tables  [============        ]
-> creating tables  [=============       ]
-> creating tables  [==============      ]
-> creating tables  [===============     ]
-> creating tables  [================    ]
-> creating tables  [=================   ]
-> creating tables  [==================  ]
-> creating tables  [=================== ]

to clutter the output of tests

prioritynormal
typebug
done in3.20.8
load0.500
load left0.000
closed by#28ec01db78b3 [server] Do not use progress bar when stdout is not a TTY
patch[server] Do not use progress bar when stdout is not a TTY [applied]