Breadcrumbs: endContent is rendered twice, duplicating interactive elements and data-qa attributes

[DR33M]

Describe the bug

endContent in Breadcrumbs is rendered twice in the DOM (measurement pass + visible pass), causing any interactive content placed there to be duplicated. This leads to two dialogs opening simultaneously on a single button click. As a side effect, data-qa attributes on elements inside endContent are also duplicated, causing tests that query by data-qa to find multiple elements and fail.

Reproduction

https://stackblitz.com/edit/gravity-ui-uikit-example-96cxtdwr?file=src%2FApp.css,src%2FApp.tsx

Steps to reproduce

1. Click the "Open Dialog" button inside the breadcrumbs
2. Observe that two dialogs open simultaneously — the counter inside the dialog shows Open modals count: 2

Environment

@gravity-ui/uikit@^7.33.0

Validations

• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• The provided reproduction is a minimal reproducible example of the bug.