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}

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Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

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

```diff @@ 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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