2323 delete paste from clipboard from dt

[kdp-cloud]

Closes #2323

[Copilot]

Pull Request Overview

This PR removes the "Paste From Clipboard" functionality from the ISA studies interface. The primary purpose is to eliminate the clipboard pasting feature that allowed users to paste data from their clipboard into data tables.

Key changes:

• Removal of clipboard paste button from the UI
• Deletion of associated JavaScript functionality for clipboard operations
• Addition of timezone testing helpers and comprehensive date formatting tests

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
app/views/isa_studies/_buttons.html.erb	Removes the "Paste From Clipboard" button and associated help text from the UI
app/assets/javascripts/single_page/dynamic_table.js.erb	Removes the pasteFromClipboard JavaScript function and related clipboard handling logic
app/helpers/application_helper.rb	Refactors date formatting logic to reduce duplication and improve maintainability
test/test_helper.rb	Adds timezone helper method for testing date formatting across different timezones
test/unit/helpers/application_helper_test.rb	Adds comprehensive tests for date formatting with timezone support

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