fix(input): by default, do not trim input[type=password] values

Previously, all input types using ngModel and textInputType() would trim values if the ng-trim
attribute was unspecified. This is undesirable for passwords because a user's input should always
be canonical in that case.

This CL changes this behaviour by only trimming by-default if the input type is not password. In
the future, if other input types need to be checked, or if the input type needs to be checked at
runtime, this may be refactored to support those cases.

BREAKING CHANGE:

Previously, input[type=password] would trim values by default. This is no longer the case, and requires
an explicit `ng-trim="value other than 'false'"` to ensure that the value is trimmed in casees where this
is actually desirable.

Example:

    <input type="password" ng-model="password"> <!-- WILL NOT TRIM VALUE -->
    <input type="password" ng-model="password" ng-trim="false"> <!-- WILL NOT TRIM VALUE -->
    <input type="password" ng-model="password" ng-trim="ANYTHING ELSE"> <!-- WILL TRIM VALUE -->