For some of the networks where favicon wasn't there, we rendered `?` for
the avatar network logo in dapp toast. This PR fix this issues and adds
a fallback to the network name when image is not there

## **Related issues**

Fixes: #24255 

## **Manual testing steps**

1. Run extension with Multichain flag
2. Connect to a uniswap
3. Switch network to Blast on dapp. Check the toast and that network
logo should be same as popup header

## **Screenshots/Recordings**


### **Before**
![Screenshot 2024-04-26 at 4 52
48 PM](https://github.com/MetaMask/metamask-extension/assets/39872794/118a442b-c3b6-4fc7-846a-7a031f2ad284)


### **After**
![Screenshot 2024-04-26 at 4 43
17 PM](https://github.com/MetaMask/metamask-extension/assets/39872794/c36ca839-6f88-403f-9a3e-704d9028c5c2)


## **Pre-merge author checklist**

- [ ] I’ve followed [MetaMask Coding
Standards](https://github.com/MetaMask/metamask-extension/blob/develop/.github/guidelines/CODING_GUIDELINES.md).
- [ ] I've completed the PR template to the best of my ability
- [ ] I’ve included tests if applicable
- [ ] I’ve documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [ ] I’ve applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-extension/blob/develop/.github/guidelines/LABELING_GUIDELINES.md)).
Not required for external contributors.

## **Pre-merge reviewer checklist**

- [ ] I've manually tested the PR (e.g. pull and build branch, run the
app, test code being changed).
- [ ] I confirm that this PR addresses all acceptance criteria described
in the ticket it closes and includes the necessary testing evidence such
as recordings and or screenshots.

Co-authored-by: David Walsh <davidwalsh83@gmail.com>