[FIX] grid: hide AddRowFooter when the mainViewport is too small

[fw-bot]

How to reproduce:

• insert a list
• freeze pane to the lowest visible row
• start scrolling to get to the bottom of the page

=> the full layout is broken

Task: 6103620

Description:

description of this task, what is implemented and why it is implemented that way.

Task: TASK_ID

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: #9389

[robodoo]

[fw-bot]

@rrahir @hokolomopo cherrypicking of pull request #9389 failed.

stdout:

Auto-merging src/components/grid_overlay/grid_overlay.ts
CONFLICT (content): Merge conflict in src/components/grid_overlay/grid_overlay.ts
Auto-merging src/components/grid_overlay/grid_overlay.xml
CONFLICT (content): Merge conflict in src/components/grid_overlay/grid_overlay.xml
Auto-merging tests/sheet/sheet_manipulation_component.test.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