[FIX] pivot: unused pivot detection

[fw-bot]

Description:

[FIX] pivot: unused pivot detection with composed formula

If a formula has two pivots (eg. =PIVOT(1) + PIVOT(2)), the
second pivot will not be detected as used.

[FIX] pivot: unused pivot detection with calculated measure

If a pivot has a calculated measure that refers to a second pivot,
the second pivot is not detected as used. This commit fixes that.

Note: the fix does not fix 100% of the issues. A pivot only referenced
in other places (eg. in a CF rule formula) will still not be
detected as used. But checking every other place the pivot can be
referenced is expensive and error-prone. That may be done in master.

Task: 6105894

review checklist

• feature is organized in plugin, or UI components
• support of duplicate sheet (deep copy)
• in model/core: ranges are Range object, and can be adapted (adaptRanges)
• in model/UI: ranges are strings (to show the user)
• undo-able commands (uses this.history.update)
• multiuser-able commands (has inverse commands and transformations where needed)
• new/updated/removed commands are documented
• exportable in excel
• translations (_t("qmsdf %s", abc))
• unit tested
• clean commented code
• track breaking changes
• doc is rebuild (npm run doc)
• status is correct in Odoo

Forward-Port-Of: #8740
Forward-Port-Of: #8539

[robodoo]

[fw-bot]

@hokolomopo @LucasLefevre cherrypicking of pull request #8539 failed.

• 57ad17a <- on this commit
• 539b4a5

stdout:

Auto-merging src/plugins/ui_core_views/pivot_ui.ts
CONFLICT (content): Merge conflict in src/plugins/ui_core_views/pivot_ui.ts

Either perform the forward-port manually (and push to this branch, proceeding as usual) or close this PR (maybe?).

you can use git-fw to re-do the forward-port for you locally.

⚠️ after resolving this conflict, you will need to merge it via @robodoo.

More info at https://github.com/odoo/odoo/wiki/Mergebot#forward-port

[hokolomopo]

@robodoo r+