Add preview_open and preview_close events to Gallery

[freddyaboulton]

Description

Closes: #6697

🎯 PRs Should Target Issues

Before your create a PR, please check to see if there is an existing issue for this change. If not, please create an issue before you create this PR, unless the fix is very small.

Not adhering to this guideline will result in the PR being closed.

Testing and Formatting Your Code

1. PRs will only be merged if tests pass on CI. We recommend at least running the backend tests locally, please set up your Gradio environment locally and run the backed tests: bash scripts/run_backend_tests.sh

2. Please run these bash scripts to automatically format your code: bash scripts/format_backend.sh, and (if you made any changes to non-Python files) bash scripts/format_frontend.sh

[gradio-pr-bot]

🪼 branch checks and previews

•	Name	Status	URL
	Spaces	ready!	Spaces preview
	Website	ready!	Website preview
	Storybook	ready!	Storybook preview
🦄	Changes	detected!	Details

---

Install Gradio from this PR

pip install https://gradio-pypi-previews.s3.amazonaws.com/684668a055035bd074125fc3fae80d91cfcfd447/gradio-5.10.0-py3-none-any.whl

Install Gradio Python Client from this PR

pip install "gradio-client @ git+https://github.com/gradio-app/gradio@684668a055035bd074125fc3fae80d91cfcfd447#subdirectory=client/python"

Install Gradio JS Client from this PR

npm install https://gradio-npm-previews.s3.amazonaws.com/684668a055035bd074125fc3fae80d91cfcfd447/gradio-client-1.9.0.tgz

Use Lite from this PR

<script type="module" src="https://gradio-lite-previews.s3.amazonaws.com/684668a055035bd074125fc3fae80d91cfcfd447/dist/lite.js""></script>

[gradio-pr-bot]

🦄 change detected

This Pull Request includes changes to the following packages.

Package	Version
@gradio/gallery	minor
gradio	minor

• Maintainers can select this checkbox to manually select packages to update.

With the following changelog entry.

Add preview_open and preview_close events to Gallery

Maintainers or the PR author can modify the PR title to modify this entry.

Something isn't right?

• Maintainers can change the version label to modify the version bump.
• If the bot has failed to detect any changes, or if this pull request needs to update multiple packages to different versions or requires a more comprehensive changelog entry, maintainers can update the changelog file directly.

[abidlabs]

LGTM @freddyaboulton! Your changes look good, but while testing this PR I noticed that the .change() event of the interactive gr.Gallery component does not fire when files are uploaded, so perhaps we can fix that as part of this PR.

Repro:

import gradio as gr

with gr.Blocks() as demo:
    with gr.Row():
        g1 = gr.Gallery()
        g2 = gr.Gallery()
    t = gr.Textbox(interactive=True)
    g1.change(lambda x:x, g1, g2)
    g2.preview_close(lambda : "hi", None, t)

demo.launch()

[freddyaboulton]

Thanks for the review @abidlabs ! Took care of that issue and modified the e2e tests to reflect the new behavior.