Align BigDecimalField default width with TextField

[web-padawan]

Describe your motivation

Originally, NumberField was using width: 8em which was removed in Vaadin 24, see

• [text-field] Default width of number-field is different from text-field web-components#1311
• fix!: remove specified width for number field web-components#5277.

However, we missed to remove corresponding styles from BigDecimalField:

flow-components/vaadin-text-field-flow-parent/vaadin-text-field-flow/src/main/resources/META-INF/resources/frontend/vaadin-big-decimal-field.js

Lines 24 to 26 in cbb62b5

	:host {
	width: 8em;
	}

Describe the solution you'd like

We should align width of BigDecimalField with other field components. This would be a breaking change.

Describe alternatives you've considered

No response

Additional context

No response

[web-padawan]

Implemented in #7481.