Remove as_grid_scan from dials.import

[graeme-winter]

Is not useful, and is misleading as it makes data into stills rather than image sequence. If we want to reinstate it, this can be reverted and fixed up appropriately.

Fixes #2452

Mentined in #2447

[codecov]

Codecov Report

Merging #2454 (8b3c9c9) into main (da59c1d) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

❗ Current head 8b3c9c9 differs from pull request most recent head 19a763c. Consider uploading reports for the commit 19a763c to get more accurate results

@@            Coverage Diff             @@
##             main    #2454      +/-   ##
==========================================
- Coverage   78.74%   78.73%   -0.01%     
==========================================
  Files         606      606              
  Lines       74096    74087       -9     
  Branches    10073    10070       -3     
==========================================
- Hits        58347    58336      -11     
+ Misses      13617    13615       -2     
- Partials     2132     2136       +4     

[ndevenish]

Given the problem last time we removed one of these, I'd be more comfortable deprecating it first?

[graeme-winter]

I take your point with this. It does not change the fact that it doesn't work and is misleading and useless, but deprecating for next release then removing after release does seem sane