erp5_user_tutorial_ui_test: dependency on erp5_accounting was missing (account_module).

runUnitTest: log_directory is imported from Unit Tests and thus must be global to avoid pylint error.

See merge request nexedi/erp5!1251

1. set 0 as default value, otherwise leaflet_display_side will always be true
2. show message instead of crash
3. correct parameters
4. clean code

Since 206a8e25 (erp5_officejs: new OfficeJS Slideshow Editor application,
2020-07-06) this test runs with erp5_run_my_doc installed, and the first export
action for Web Page is no longer "Export as SlideShow" but "Export as Chapter".
This is an action which is here since a long time in erp5_run_my_doc, but since
erp5_run_my_doc was not installed in this test it was not impacting this test.

Adjust the tests so that they don't assume that the first export action is
"Export as SlideShow" but are more independent on which is the first action.

Also, all actions have a new index, so places where we select the action by
index no longer work. Instead of updating the indexes, select by label which
should be more future proof.

Mathematically, 1/(x^y) is the same as x^-y, and despite float caculation the results is usually precise enough :
> Math.pow(10, -5)
0.00001
I tested this on few platforms : firefox 68.12, firefox 77.0, node v10.19.0

Unfortunately on (recent ?) chromes :
> Math.pow(10, -5)
0.000009999999999999999
Which is a horrible value to use as step (and it prevents the form submission as most floats the user will enter won't match the init value * x * the step.

For an unknown reason, I get a more consistent result using the formula "1 / Math.pow(10, 5)", which returns 0.00001 on all tested platforms.

If we find more issues in the future, we maybe should try building the step using strings. Using strings for manipulating floats is in reality widespread, and many languages do so to round floats (ie: https://github.com/python/cpython/blob/4a97b1517a6b5ff22e2984b677a680b07ff0ce11/Objects/floatobject.c#L925)

The precision of 5 is not random-picked, it is the minimum precision needed to manipulate prices for currencies with 2 digits, like euros.

When portal_contributions.PUT() is called, Document was not converted (and `base_data`
was not set) by document_conversion_interaction_workflow as this was only done on
_set{Data,File}() and OFS.Image.update_data() sets `data` property directly.

This fixes failures on testWebDavSupport.test_GET_on_{contributionTool,document}
with erp5_full_text_*_catalog bt5 installed: SQLCatalog_deferFullTextIndexActivity
Activity failing with `NotConvertedError` when trying to convert to txt as
`base_data` is not set.