Navigation - Don't reprocess fully-formed urls

[colemanw]

Overview

Fixes an edge-case bug where fully-formed relative urls were being reprocessed and messed up in the menubar.

Before

Urls starting with a forward slash would end up with two slashes in front and garbled params.

After

Relative urls, absolute urls, and local urls all processed correctly.

Technical Details

CRM_Core_BAO_Navigation can handle both internal and external urls, however it was incorrectly handling urls that started with a forward slash as it didn't correctly identify them as already processed and tried to run them through CRM_Utils_System::url() again.

[civibot]

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[lcdservices]

@colemanw tested and confirmed. I could reproduce the error by creating a new navigation item with a leading slash. After applying the patch and clearing cache, the menu link worked as expected.