client: support offline flag in config command

[jgimeno]

Closes: #5855

Description

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For contributor use:

• Targeted PR against correct branch (see CONTRIBUTING.md)
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Code follows the module structure standards.
• Wrote unit and integration tests
• Updated relevant documentation (docs/) or specification (x/<module>/spec/)
• Added relevant godoc comments.
• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md
• Re-reviewed Files changed in the Github PR explorer

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For admin use:

• Added appropriate labels to PR (ex. WIP, R4R, docs, etc)
• Reviewers assigned
• Squashed all commits, uses message "Merge pull request #XYZ: [title]" (coding standards)

[codecov]

Codecov Report

Merging #5856 into master will increase coverage by 0.03%.
The diff coverage is 62.50%.

@@            Coverage Diff             @@
##           master    #5856      +/-   ##
==========================================
+ Coverage   56.78%   56.82%   +0.03%     
==========================================
  Files         342      342              
  Lines       20047    20044       -3     
==========================================
+ Hits        11383    11389       +6     
+ Misses       7815     7805      -10     
- Partials      849      850       +1     

[alessio]

Nice one! Please update and test the changes with gaia once this is merged

[alessio]

There is an unexpected change that needs to be addressed

[alessio]

It's all good