Improve field accessibility in legacycustomsearches

[braders]

Overview

Improve field accessibility in legacycustomsearches

Before

1. First label was double nested (<label><label>...</label></label>)
2. Second field had no accessible label

After

Accessibility improved.

Comments

I appreciate that the legacy searches are on their way out, but it felt appropriate to fix as its such a small change.

[civibot]

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[colemanw]

Good change!