.slds-file-selector__text.slds-medium-show {
  display: none; 
}
.slds-file-selector_files .slds-file-selector__text{
    margin-left: var(--lwc-spacingXSmall,0.5rem);
    margin-right: var(--lwc-spacingSmall,0.75rem);
    display: none;
}