Remove solidus 4.0 constraint

[DanielePalombo]

No description provided.

[rakvium]

@kennyadsl as I see, this pull request was approved and this code works with Solidus 4.5.0 - may it be merged into this repository?

[rakvium]

There are some deprecation warnings, but I guess they may be resolved in the next release 🤔

DEPRECATION WARNING: Passing sections to Spree::BackendConfiguration::MenuItem is deprecated. Please pass a label instead. (called from new at /home/path_to/.rvm/gems/ruby-3.3.8/bundler/gems/solidus_reports-47d0a1c29481/lib/solidus_reports/engine.rb:22)
DEPRECATION WARNING: Passing icon to Spree::BackendConfiguration::MenuItem is deprecated. Please use the keyword argument instead. (called from new at /home/path_to/.rvm/gems/ruby-3.3.8/bundler/gems/solidus_reports-47d0a1c29481/lib/solidus_reports/engine.rb:22)
/home/path_to/project/app/overrides/store_credit_category_everrides.rb:3: warning: already initialized constant Spree::StoreCreditCategory::PROMOTION
/home/path_to/project/app/overrides/store_credit_category_everrides.rb:3: warning: previous definition of PROMOTION was here

[kennyadsl]

@rakvium hello there! Would you mind rebasing this PR against the main branch (it's also ok to open a new PR) to see if specs are still green?