BLF Filter No import if preview in importdialog is hidden

Steps to reproduce

1. Open import dialog
2. Select file other than .blf
3. Hide Options
4. Select blf file
5. Import

Expected

Importing correctly

Observed

No data will be imported

Release build 2.9.0-1574-gf5676879e
Feb 13 2023, 04:32:01
System: Windows 10 Version 2009
Locale: English,United States (Decimal point '.', Group separator ','
Number settings: Decimal point '.', Group separator ',', Exponential 'e', Zero digit '0', Percent '%', Positive/Negative sign '+'/'-' (Updated on restart)
Architecture: x86_64-little_endian-llp64
Kernel: winnt 10.0.19043
C++ Compiler: MSVC 19.29.30147.0
C++ Compiler Flags: /DWIN32 /D_WINDOWS /W3 /GR /EHsc /wd4250 /wd4251 /wd4396 /wd4661 /Zc:__cplusplus -O2 -W3 -DPSAPI_VERSION=1