Inconsistent Commit Hash Length

### Is your feature request related to a problem? Please describe.

There is an inconsistency in commit hash display lengths across different sections of lazygit. The commit log view displays 6-character hashes while the Commits section displays 7-character hashes. This inconsistency affects readability and creates confusion when referencing commits across different UI panels.

### Describe the solution you'd like

Standardise the commit hash length to be consistent across all views in lazygit (commit log, commits section, branches view, tags view, and any other UI elements that display commit hashes). All commit hashes should display the same number of characters throughout the application.

### Additional context

The inconsistency was observed in the lazygit interface where:
* The commit log panel displays 6-character hashes
* The Commits section displays 7-character hashes

This should be standardized across all views showing commit hashes for consistency and better user experience.