Update User Details

#### User Story:
> Existing user can update their details.

#### Pre-requisites:
- [ ] User DAO (update)
- [ ] User Service (update)

#### Validations:

- [ ] Form Validation:
- Id <= 0
- User Object
- User null
- Name ( null, empty, pattern )
- Password ( null, empty, pattern )
- Phone number ( length, >= 600000001 && <= 9999999999 )

- [ ] Business Validation:
- Check whether the Id exists.

#### Messages:
- User Id cannot be less than zero.
- User object cannot be null.
- Name cannot be null or empty.
- Password cannot be null or empty.
- Password does not match the pattern.
- Phone number cannot be less than or more than 10 digits.
- Phone number does not match the pattern.
- Id doesn't exists.

#### Flow:

```mermaid
graph TD;
A(Value Passed to UserService - Id & User object) --> B(Form Validation) -- Valid --> C(Business Validation)
B --Invalid --> H(Validation Exception)
C -- Valid--> D(Value Passed to UserDAO)
D --> E(Update value from Database)
C -- Invalid --> F(Validation Exception)
```