Fix shrinking logo in safari

[sl1depengwyn]

Part of #6437

Motivation

.png images were shrinking in Safari browser

Changelog

Changed default width value for logo from 100% to auto

before:

after:

Checklist for your Pull Request (PR)

• I added an entry to CHANGELOG.md with this PR
• If I added new functionality, I added tests covering it.
• If I fixed a bug, I added a regression test to prevent the bug from silently reappearing again.
• I checked whether I should update the docs and did so by submitting a PR to https://github.com/blockscout/docs
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• If I add new indices into DB, I checked, that they are not redundant with PGHero or other tools

[vbaranov]

This parameter could be defined for some client setups. Probably, we could keep its usage, but change the default 100% to auto?

[sl1depengwyn]

Good point, fixed