Created attachment 172183 [details]
Example file from Excel

Attached example file shows two simple line charts with many data points.
The top one has Text type X axis, while the bottom one has Date type X axis, both rotated to 90 degrees.
The top one displays the axis labels for all of the data points making them slip together, while the bottom one skips some to keep them readable.

Steps to reproduce:
    1. Open attached file

Actual results:
The top chart shows too many X axis labels, making them unreadable.

Expected results:
The top chart should skip the display of some X axis labels, just like the bottom one does.

LibreOffice details:
Version: 7.2.0.0.alpha1+ (x64) / LibreOffice Community
Build ID: 91330c503b7eb91d777978018b66890af87cf8f5
CPU threads: 4; OS: Windows 10.0 Build 18363; UI render: default; VCL: win
Locale: hu-HU (hu_HU); UI: en-US
Calc: CL

and
Version: 7.1.0.3 (x64) / LibreOffice Community
Build ID: f6099ecf3d29644b5008cc8f48f42f4a40986e4c
CPU threads: 4; OS: Windows 10.0 Build 18363; UI render: default; VCL: win
Locale: hu-HU (hu_HU); UI: hu-HU
Calc: threaded

Not yet in:
Version: 7.0.0.3 (x64)
Build ID: 8061b3e9204bef6b321a21033174034a5e2ea88e
CPU szálak: 4; OS: Windows 10.0 Build 18363; Felületmegjelenítés: alapértelmezett; VCL: win
Locale: hu-HU (hu_HU); UI: hu-HU
Calc: threaded

Additional Information:

Bibisected using bibisect-win64-7.1 to:
URL: https://cgit.freedesktop.org/libreoffice/core/commit/?id=189a12a1d4d96b8656bd1a0588e1bb7ddd167f40 
author	Tünde Tóth <toth.tunde@nisz.hu>	Mon Nov 23 15:05:24 2020 +0100
committer	Xisco Fauli <xiscofauli@libreoffice.org>	Tue Nov 24 15:01:15 2020 +0100

tdf#138194 Chart OOXML import: set text break to true

Adding CC to: Tünde Tóth