[BUGFIX] Fix condition in EXT:impexp to check for export view

The check for `inData.action` didn't work anymore for a long time as
`action` is not set in the controllers anymore. To check if we're in the
export view, the existing check for `import.mode` is re-used instead.

Resolves: #98258
Releases: main, 11.5
Change-Id: I7ce3e572d2fe90ded1f6d100461c616b0b768e5f
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/75604


Tested-by: core-ci <typo3@b13.com>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>