Add restrictions to claim and make the claim optional in custom policy

[LearnToCodeKM]

I am trying to add collect user details using LocalAccountSignUpWithLogonName custom policy.I have added <OutputClaim ClaimTypeReferenceId="email" />
to LocalAccountSignUpWithLogonName as outputclaim. I want to make the email field optional, but if user enter the email I want to enable the restrictions.Below is my email claim
<ClaimType Id="email"> <DisplayName>Your Email Address</DisplayName> <DataType>string</DataType> <DefaultPartnerClaimTypes> <Protocol Name="OpenIdConnect" PartnerClaimType="email" /> </DefaultPartnerClaimTypes> <UserHelpText>Email address that can be used to contact you.</UserHelpText> <UserInputType>TextBox</UserInputType> <Restriction> <Pattern RegularExpression="^[a-zA-Z0-9.+!#$%&amp;'^_{}~-]+@[a-zA-Z0-9-]+(?:\.[a-zA-Z0-9-]+)*$" HelpText="Please enter a valid email address." /> </Restriction> </ClaimType>

But when I add the pattern restriction to claim its making the field mandatory.
It is possible to make the claim optional with restrictions.