fix: refactor guess_layer_format() for more robustness

[maelle]

Fix #158
Fix #157

@salvafern could you please have a look?

wfs <- EMODnetWFS::emodnet_init_wfs_client(service = "physics")
#> Loading ISO 19139 XML schemas...
#> Loading ISO 19115 codelists...
#> ✔ WFS client created successfully
#> ℹ Service: "https://prod-geoserver.emodnet-physics.eu/geoserver/ows"
#> ℹ Version: "2.0.0"
str(EMODnetWFS::emodnet_get_layer_info(wfs, layers = "EP_PLATFORMS_MO_ATLAS"))
#> rowws_df [1 × 9] (S3: rowwise_df/tbl_df/tbl/data.frame)
#>  $ data_source    : chr "emodnet_wfs"
#>  $ service_name   : chr "https://prod-geoserver.emodnet-physics.eu/geoserver/ows"
#>  $ service_url    : chr "physics"
#>  $ layer_name     : chr "EP_PLATFORMS_MO_ATLAS"
#>  $ title          : chr "EMODnet Physics - Moorings - ATLAS"
#>  $ abstract       : chr "EMODnet Physics DB of the mooring. Global collection. \r\nA mooring in oceanography is a collection of devices,"| __truncated__
#>  $ class          : chr "WFSFeatureType"
#>  $ format         : chr "data.frame"
#>  $ layer_namespace: chr "EMODnet"
#>  - attr(*, "groups")= tibble [1 × 1] (S3: tbl_df/tbl/data.frame)
#>   ..$ .rows: list<int> [1:1] 
#>   .. ..$ : int 1
#>   .. ..@ ptype: int(0)

^{Created on 2024-02-28 with reprex v2.1.0}

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.20%. Comparing base (8b52b4d) to head (fbedf57).
Report is 8 commits behind head on main.

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Additional details and impacted files

@@            Coverage Diff             @@
##             main     #159      +/-   ##
==========================================
+ Coverage   86.43%   88.20%   +1.76%     
==========================================
  Files           9        9              
  Lines         339      339              
==========================================
+ Hits          293      299       +6     
+ Misses         46       40       -6     

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