[7.x] Fix merging boolean or null attributes in Blade components

[sileence]

The fix to escape merged attributes with e creates an unexpected behaviour when merging attributes with null or boolean values, for example:

        $bag = new ComponentAttributeBag([]);
        
        echo $bag->merge([
            'required' => false,
            'readonly' => null,
            'disabled' => true,
        ]));

Will print required="" readonly="" disabled="1" instead of disabled="disabled"

This is also inconsistent with the result that we'd get if we create a new instance of ComponentAttributeBag passing the same array as the first argument of the constructor:

new ComponentAttributeBag([
    'required' => false,
    'readonly' => null,
    'disabled' => true,
])

Will print disabled="disabled" and I think this is the right result.

Therefore I'm submitting this PR to avoid escaping boolean or null values so we get the same result in both cases.