fix: support custom headers

[gergelylovas]

Description

https://ava-labs.atlassian.net/browse/CP-13960

Related PRs:

• VM-modules: feat: custom rpc calls headers core-vm-modules#413
• Avalanche-sdks: https://github.com/ava-labs/avalanche-sdks/pull/783

KNOWN LIMITATION:
Custom headers are not used for the built in Swap feature

Changes

• Updates SDKs to support custom headers for networks
• Improves the custom header input fields

Testing

• Set a custom header in the network list for one of the networks
• Do interactions with the network (send, balance fetch, rpc calls via connector) etc.
• Check if headers are included in the requests on the networks tab

Screenshots:

Checklist for the author

Tick each of them when done or if not applicable.

• I've covered new/modified business logic with Jest test cases.
• I've tested the changes myself before sending it to code review and QA.

[Copilot]

Pull request overview

This PR targets adding support for custom headers (CP-13960) by updating Avalanche-related SDK/module dependencies to a prerelease build that includes the needed functionality, and by refining the UI behavior of the key/value header input field to better handle focus and label display.

Changes:

• Pin multiple @avalabs/*-module packages (and related deps) to a prerelease build via Yarn lockfile + workspace dependency updates.
• Bump @avalabs/avalanchejs from 5.1.0-alpha.2 to 5.1.0-alpha.3 in affected workspaces.
• Update KeyValueFormField to track focused sub-field and adjust caption visibility/focus clearing behavior.

Reviewed changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
yarn.lock	Updates lockfile to pull prerelease @avalabs/*-module builds and introduces @avalabs/avalanchejs@5.1.0-alpha.3.
package.json	Pins @avalabs/*-module packages to the prerelease build via resolutions.
packages/ui/package.json	Updates @avalabs/avalanchejs and @avalabs/vm-module-types to the new pinned versions.
packages/service-worker/package.json	Updates Avalanche module dependencies to the prerelease build and bumps @avalabs/avalanchejs.
packages/inpage/package.json	Updates EVM/SVM modules to the prerelease build.
apps/next/package.json	Bumps @avalabs/avalanchejs and pins @avalabs/vm-module-types to the prerelease build.
apps/next/src/components/Forms/KeyValueFormField.tsx	Adds focus-state tracking to improve label/caption behavior when editing key/value header rows.

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[csabbee]

[bohdan-struk-avalabs]

looks good to me!