feat: increase keyboard font size for classic theme (#897)

## Summary

* **What is the goal of this PR?** (e.g., Implements the new feature for
file uploading.)

Adresses Feature Request #896 

* **What changes are included?**

Changed key dimensions, initial positions and margins.

## Additional Context

The keyboard now looks like this:

![image](https://github.com/user-attachments/assets/e2b8f3fe-e54a-4a44-9a29-2ef9f2c8dffb)

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### AI Usage

While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.

Did you use AI tools to help write this code? _**NO**_

src/components/themes/BaseTheme.h

@@ -90,9 +90,9 @@ constexpr ThemeMetrics values = {.batteryWidth = 15,
                                  .sideButtonHintsWidth = 30,
                                  .progressBarHeight = 16,
                                  .bookProgressBarHeight = 4,
-                                 .keyboardKeyWidth = 18,
+                                 .keyboardKeyWidth = 22,
-                                 .keyboardKeyHeight = 18,
+                                 .keyboardKeyHeight = 30,
-                                 .keyboardKeySpacing = 3,
+                                 .keyboardKeySpacing = 10,
                                  .keyboardBottomAligned = false,
                                  .keyboardCenteredText = false};
 }