Tiled Gallery images sizes inconsistent between editor and front of site causing layout issues

### Impacted plugin

Jetpack

### Quick summary

When investigating 9474377-zd-a8c I determined that the image sizes are different between the editor and the front end. Specifically the aspect ratios are different.

- go to the page in question on the support ticket
- open a support session and Edit the page
- ensure you have two browser windows open tiled next to each with the same widths - one should be the editor and the other the front of site
- using DevTools select the first image in the gallery
- switch to Console and type $0.currentSrc.
- Repeat for both editor and front of site.
- Compare dimensions and notice they are different.

It's easier to perceive the diffetent when you remove the `flex-basis` rules from `.tiled-gallery__col`. Again use dev tools and add `flex-basis: initial !important`.

### Steps to reproduce

Visit the page mentioned in the support ticket and open in editor and front of site views. You can visually see the different layouts.

### Site owner impact

Fewer than 20% of the total website/platform users

### Severity

Moderate

### What other impact(s) does this issue have?

_No response_

### If a workaround is available, please outline it here.

_No response_

### Platform (Simple and/or Atomic)

Simple
Atomic
Jetpack

Start with the affected page and compare the first gallery image's currentSrc and layout in the editor and front of site using two same-width browser windows. Inspect the .tiled-gallery__col flex-basis behavior in DevTools; done means both views use consistent image dimensions and no longer produce visibly different gallery layouts.

Written by the indexing model from the issue text.