add base fee chart, safe and finalized blocks to monitor

[tclemos]

• For EIP-1559 compatible networks, replace Gas Price chart with Base Fee chart
• Adds Safe and Finalized block numbers to header
• Reorganize header fields

closes https://github.com/0xPolygon/devtools/issues/200

[Copilot]

Pull Request Overview

This PR updates the monitoring UI to support EIP-1559 by replacing the gas price chart with a base fee chart and displaying safe and finalized block numbers in the header.

• Replaces gas price chart with base fee chart for EIP-1559 networks.
• Adds safe and finalized block numbers to the header.
• Updates the UI and monitor logic to handle the new fields and reorganizes header layout.

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
metrics/metrics.go	Adds GetMeanBaseFeePerBlock function for calculating base fees.
cmd/monitor/ui/ui.go	Updates GetCurrentText and SetUISkeleton to display safe/finalized blocks and adjust chart title based on EIP-1559 support.
cmd/monitor/monitor.go	Fetches safe and finalized block headers; integrates EIP-1559 support into monitor logic.

Comments suppressed due to low confidence (1)

metrics/metrics.go:116

• [nitpick] Consider renaming the variable 'fee' to 'baseFees' for improved clarity in representing the base fee values.

fee := make([]float64, 0, len(bs))